Moneyshot: I too do AFI work here and there around London, and the plain fact is there aren't enough students coming forward to keep everyone in business. We British contrive to make learning to fly difficult, expensive and unrewarding, and especially so with helicopters. It's not that the jobs are "jealously guarded." People who have them are by and large keen to move up.
Keep trying. You're better qualified than most, and I'm sure you'll find something now that the weather is picking up. It's the Bank Holiday weekend - anyone who can't sell flying time this weekend should give up.