ILR: Qualified accountant ACCA

[Janaan]

I am applying for ILR in Sep on Tier 1G. I am self employed and therefore need an accountant who is the member of UKBA authorized bodies. When I doubled checked with my accountant who has been managing my accounts, he is not the member of UKBA authorized bodies but few others. However he suggested that another accountant who works for the same accountant firm is a member of ACCA and according to him UKBA should not have any problems as he is a member of ACCA. My question is will I be ok getting a letter/invoice summary etc from this other accountant? It will be on the headed paper of the same accountant firm which is not the member of UKBA authorized bodies. Or shall I get a letter from ACCA member accountant in his individual capacity even if he does not have his own letter head as he works as an employee there? Also is it the accountant firm or the individual accountant associated with it has to be the member of UKBA authorized accountant bodies?

I am very confused and there would really appreciate if any one can advise please. I was thinking to move to another accountant to avoid taking any risks but at this stage when I have few weeks left moving accountant may cause more trouble.

Regards