I would like to offer a suggestion...
I am a complementary therapist and along with KashFlow I started to use a very specific Client Management System... one at my own practice and the other where I work with my colleague. They are both great for us and they even send invoices after sessions. I was wondering if you would consider integrating them (or something similar) with KashFlow.
The CMS we use is Cliniko.com and WriteUpp.com.
Neither of them takes payment on booking. However, there is another one (YouCanBook.me) which integrates with Stripe, but it's not as simple to use as the other two. Well, just an idea.
Do keep up your good work.