I see that he calls MWT Mark Thomas-Williams! MWT's messages seem the right response and it's interesting that Jeremy Vine might do a documentary on Alex Belfield. I'd never heard of him. Went looking online and found these.
Who is Alex Belfield? (a self obsessed tyrant)
STOP! Alex Belfield -UPDATED (judging by the BBC's supportive response to the blogger I wonder if Belfield's short time at the BBC had been marred by bad behaviour)
He seems to be a childish idiot, projecting his own failings onto other people, but still capable of causing a lot of worry and grief.
The only thing going for him is a "broadcasterish" voice - perhaps just the kind of voice JK would approve of, as it's not female or squeaky.