What sort of software/app should I be using for my bookings?

There are dozens of WordPress booking plugins that will meet your needs. Search WordPres.org.

If you're not using WordPress there are many that work in HTML sites via CGI (yes, it's still a viable method).

Google is your friend.

Frank

I faced similar problems. After a lot lot lot of time spent researching I ended up with Timely (Gettimely.com).

Email/ SMS reminders, staff allocation, invoicing, Stripe, calendar etc. Plus a really nice booking system you can embed on your website / Facebook page so customers can book themselves without even needing to contact you. Mobile & tablet apps too. Integrates with Google calendars etc so you can still use them if need be (e.g. staff can put on their phones so they know when they have an appointment).

Functions extremely well, a lot of features. Inexpensive & easy to use. You'll never look back.

Timely looks good.

I was going to suggest using Zapier to automate a lot of the functions but I reckon an integrated system like Timely would be better in the long run.

Check out Mind Body you can get started for $75 a month

why not just use paypal like most others. they have an invoicing feature built in, and the customer can pay via credit card, they do not need to have a paypal account.. for the life of me, I can not figure out why people over complicate things so much.

al

So great that you wrote out your workflow!
Ok for fun I looked at all your steps and made recommendations. I think there are some ways you can save time and improve customer service. I will assume you have been in business for years, have repeat and referral customers, and business is growing. Not only are you feeling overloaded now, but next year will be more so due to your success!

1. We get enquiries, mostly via email/contact form on website
2. Some back and forth via email

The initial contact form can be automated, but you also have email and I presume phone and in-person enquiries too.
This is the top of your sales funnel.
Continue your manual process because customers expect your good personal treatment.

Change: Your spreadsheet (Excel?) is your database. Start adding all info from the enquiry to the spreadsheet religiously from the beginning. Even if the customer does not commit this time, their info is now captured for your future email campaigns.

3. Submit an invoice, which is written in Microsoft Word.

Change: Forget MS Word invoices. Too manual and actually less business-like than accounting system invoices. Use an online invoicing application. I have used Freshbooks just for invoicing and time tracking, and there are many competitors. (Let me just assume Freshbooks for now). Invoices look good, nice to have financials in one place, easy to run monthly and end-of-year reports.

4. Client pays, which they need to notify us that they've made payment

You don't say how they pay. Mail a check? Online credit card? Paypal? Phone with a credit card? Cash? I will assume a small business has to handle all cases, so no change here.

When paid, record the receipt in Freshbooks and in the spreadsheet.

5. We send them a link to an on-line booking form (again, a contact form on website that get saved as a Word Doc)
6. Input their details onto a bookings spreadsheet

Oh, Word docs again. This is a good place for more efficiency. Having a form for the customer to fill out is a good idea, but make sure the form is programmed to prevent bad and missing data. The form doesn't have to be on your website. You could use Typeform, or a Google Form.

Change: The contact form output should feed directly into your master spreadsheet. If that sounds scary, then it should at least feed into a temp spreadsheet which you can review, then copy and paste into the master (the block should fit perfectly with one copy/paste operation because the columns match).

7. Assign a guide for them, that also goes onto the same spreadsheet

No change. I assume scheduling trips and guides is complicated and the most important part of the process and needs human control.

8. The information is transposed (Client name, dates, guide etc.) onto a Google Calendar

Change: The calendar is programmed to continually update from the spreadsheet. The spreadsheet is your database. Another case is someone calls to change a date: you simply update the spreadsheet, and the calendar adjusts automatically.

Summary

Spreadsheets are ok for small databases. I assuming you are using Excel. I recommend Google Sheets over Excel, it is online and integrates with things. Plus you and your assistants can view and update from anywhere. Put some thought into the spreadsheet columns (fields) and add them as needed for future data mining.

Use something like Freshbooks for invoicing. You don't need a complicated accounting system.

Hire a local tech person to automate your booking-form-to-spreadsheet integration. Done right, there will be less human errors and better data versus all this MS Word and transposing work.

How fast do you need to respond to enquiries? I assume this is interruptive now, and that you respond in real time. Consider changing your workflow to do this one time a day. Also you could hire someone local who once daily reviews the new enquiries and booking forms and adds to the spreadsheet. Maybe an aunt or retired uncle!

As a high tech alternative, a CRM system would be nice but probably overkill. It would contain your customer database instead of spreadsheet, it could output invoices, do the booking forms, and calendaring. On the other hand it would require training and maintenance time that you are trying to decrease now.
Ok hope that helped a little! -phil

One of my clients was using this for their vacation rental site:

TheBookingButton - Hotel Reservation & Online Booking Engine

Has anyone got any experience of using Zoho? I've just come across it, and it looks like it may have most of the features I'm looking for to make my life a bit easier when it comes to taking a booking.

Hey Ken,

I have a client who runs one of the larger diving schools in Koh Samui, Thailand (4 boats - 60 divers per day - multiple course being run in parallel), and after a lot of searching around and trialling a bunch of stuff we settled on Bookeo.

It handles payments and invoicing, and has a bunch of stuff you can do. The UI is not pretty at all, and I'm still not 100% thrilled with how it looks on the website, but it's actually pretty powerful under the hood.

In terms of the future I figure that making things prettier is a lot easier than adding a bunch of functionality, so while it's not the prettiest, Bookeo was what we went with. Client is still really happy with it after 6 months, which is a win in my book!

For the record, I've now started using Xero Accounting Software, which seems to be quite good. Still early days yet, and haven't got much automated, but I think it's a good step forward.