Just because he's a millionaire ex-banker who appears a bit smug sometimes, he should not be barred from claiming legitimate expenses. And £900 per month is a lot of money (although he probably receives more than that in interest every month). And if he wanted to keep his sexuality under wraps, perhaps he would have been better off by not claiming at all for his accommodation arrangements. Especially as those arrangements looked a bit dodgy even before the rules were clarified.
Furthermore, the expenses row over the past year provided him with the opportunity to sort matters out, relatively quietly. An opportunity which he chose not to take.
But, hey, we all make mistakes, though not often to the extent of putting the career at risk. So move along, nothing to see here. But it's going to end in tears, isn't it?