What have support said about that, again, there should be no restrictions on allowing a withdrawal.
Has he tried doing it by bank transfer?
I just asked him Colin. He said that he can only e-mail support which he did on 11 and 18 May asking how he can lock or withdraw his winnings seeing as they restricted his account, still no response. He can't do anything on his account except 'play' the balance of £3000 in his account.
I would imagine Jumpman are trying to frustrate their players just to play their winnings back, it sure looks that way.