Turns out I didn’t mistype my email, what they read back to me was the right one. Fair play to them, they sent the booking to me on email straightaway. Lessons learnt from this - if you want to speak to them, call them as soon as they open at 9am otherwise it’s a long wait.
To quote the web, when a company starts putting a message on the phone about an unusually high amount of calls, it’s not. They just don’t want to employ anyone else to handle the call volume!