If they don't spend it, what are they going to do with it?
I can't see him trousering it as there'd be uproar. Possibly a partial repayment of the 'loan' but again, that goes against guarantees MA has given and isn't in his best interests anyway. Leaving it sitting in the bank is the other option but seems rather pointless and the interest earned would be a pittance to a man used to seeing his money divide like amoebae.
Suppose if we bank £40m a year then eventually the interest payments would go a long way towards operating costs but that's the shittest idea in the world.