I remember when the quarters at Medmenham were regraded (probably around 2005?) and they discovered that they had been over-graded some years before.
"Can we have our over-payment of rent back, please?"
"No, it's being written off. What's done is done. It's too late now."
Hmm. Why aren't I surprised?
A few years before that, Admin at Waddington had over-paid me allowances. When I pointed it out to them, OC Admin set PNSS on me who arrested me for fraud. Of course, they threw the whole thing out (after keeping me waiting for 7 months). All OC Admin had to say was,
"Well, you shouldn't have taken it in the first place. Now pay it all back."
"Er, just the over-payment!"
"No, all of it, then you can claim what you should have had."
"I did that once already"...