I have just run into this problem too... Apparently it's £5 a month administration fees.... Hahaha absolutely gobsmacked at the cheek of it.
Be aware these clowns try to charge you if account is left inactive. If you have a small balance left you cannot close account and cannot spend small balance
Cold . Offer for new customers only. But they auto subscribe and no offers and full price for existing customers . So be careful if signing with them .
One thing I really do like about HUKD is the general antipathy towards gambling 'deals'!
I used a voucher code with these guys. It was displayed as the right amount they debited the wrong amount. I queried it with them , they refused to refund me. Happened to at least two other HotUKDeals members. Could only imagine how difficult it would be to recoup your winnings.