Licensed MAAT looking to study further - where to next?

I have a bit of a conundrum if anyone has any advice. I am looking to further my studies. I became a licensed member in practise a few years ago and I am at the last step to FMAAT status. Here is my conundrum, I would like to study further, particularly for a more in depth knowledge of Corporation Tax with a view to taking on Limited Companies. This is currently not a service I offer, as I don't feel confident doing so yet. I have plentiful Sole Traders and Partnerships etc, but would like to stop having to knock back Limited work. Here's the problem, I run a company full time and as such, I do not have the time/finances to give it all up and go back to school full time. Here's an additional problem, it's physically impossible for me to study towards qualifications such as ACCA, without giving up my practising license with AAT and therefor my company.

Has anyone any guidance on a qualification I can do, without having to give up my practising license with AAT to do it?

Any help is greatly appreciated.