My fixed account for my 400,000 baht Extension of Marriage finishes approx 6 weeks before my Extension of Marriage expires and I intend to put the money straight into another fixed account, will have I any problem from immigration saying that it hasn't been in an account for 2 months prior to applying for the new Extension of Marriage ?

Good question, I would say leave the money in the account and don't move it.

Don't move it or you will have to start the 60 days over again.

Immigration considers an account change the same as going to zero in your account.

Thanks guys !