I also use Writeupp and I have just switched over to Quickfile for my accountancy package. I pay the extra £15 per year with Quickfile to get the bank feed and have started sending invoices from there. It’s running pretty smoothly! From the ‘dashboard’ I can see what money is owed and the client view shows their payment history. I can send automated reminders for late payments etc. Basically there are more features for invoicing using an accountancy package than a case management package, as you would expect.
I took a quick look at Charlotte’s recommendation about the Starling business bank account, which looks awesome. although the bank feed feature on Quickfile covers this aspect.
The great thing is you can trial most applications for free these days so you can get a feel for what suits you. And Writeupp customer service is excellent, so can get immediate responses on how to streamline your functions.
Good luck with it all and welcome to independent practice!