William Hilll will never close your account for winning. They use a different method. On each event they have a maximum amount that you may bet on it. When you are a new customer, they will allow you to bet a 100% of that maximum. If you prove to be a loser in every sport, they will continue to allow you to bet up till a 100% of that maximum, but the moment you start winning on a certain sport a little too much, they will then only allow you to bet up till a certain % of that maximum and that certain % can drop to 5%.
William Hill was not my first off-shore (which was Ladbrokes in Gibraltar) account, but they were my first on-line account back in 1998. My first payout then took over two weeks instead of the promised 2 days, so I was confronted with the fvck you around procedure first time already.
These days William Hill does pay fast. You will not hear me complain about that anymore, but they have become a totally useless book! One will simply always find a better price on BetFair!