You need the MatB1 form as above, but the form you need to claim MA is MA1, Downloadable.
In addition its worth doing a search for the Decision Makers guide which tells you all the cans and cannots according the guys that make the decision. This also helps when they tell you that you can't claim if you are working at all. You are allowed 10 days keeping in touch days, after that any work you do is a detriment to your allowance.
Seems bonkers that they want you to work and keep your business running paying tax, yet they make it difficult to do that when they take away the allowance when you do work.
Ask me how I know? couple of years ago I went through the same, ended up working 1 day a week and losing some MA, worth it to keep the business running.
But def get the guide and refer to that went the spotty kid at the office tells you any work you do will stop the MA.
