Parliament has published a list of expenses repayments made by MPs in the period 1st April, 2009 to 18th December, 2009. You can see it for yourself here
There are two entries for Mr Mann and each has a comment added by Mr Mann.

We’ll happily accept the comment on the £10.36 grocery bill, but the other, for £2,395.02, is a bit harder to swallow.
Rather than alter published totals, I have chosen to repay the full amount.
Eh? Rather than alter published totals?? Right. Kiss off £2,300 to avoid inconveniencing a computer.
Is this the same John Mann who, on his website, is asking for donations of a fiver to help fund his election campaign?
Perhaps he is keen to avoid further scrutiny of the actual expenses claimed and is willing to lose the money to cover up something he’d rather the voters did not know.
You would have thought that a proper course of action would have been to reclaim the amounts to prove that they were, in fact, legitimate. He’s entitled to the money. Isn’t he?
If Mr Mann wishes to give us an account of the expenses, we’ll publish it for all to see. He is, after all, the first one to start screaming at any hint of impropriety in expenses claims and should welcome the opportunity to clarify the situation.
We’ll leave you to decide what to believe.