some IO's, like KK say that they don't do the combination method. But I bet if you wanted to clarify that with the Head of Immigration at an office, then I'm sure the individual IO's may change their mind.
I verified my by 12 months bank statements from outgoings from UK via WISE and then shown into Bangkok Bank as international transfer. I did change my Bank account name to my name - Pension fund. No snags at IO what so ever
UK embassy doesn't provide affidavits regarding monthly income. I proved my monthly funds by UK bank statements thru to proof of international transfer by WISE and by bank statement from Bangkok bank