Hey, so I've finally had success with this method, although the casino at which I did so had a brilliant offer.
The casino was
Vegas Towers, and they offer a £50 bonus with a £50 deposit. The good part is that there is no playthrough, so anything you win, you can withdraw at any time. The bonus gets credited to the account straight away, so if you deposit £50, the balance will be £100, none of this slow release stuff. However, you can't withdraw the bonus, so its not a free £50 that you can withdraw without playing.
I played a variety of games, and WAS £120 up in about 40 minutes. I was being fairly reckless as I thought if I lose the bonus £50, I can just withdraw my deposit and leave it at that. I got bored after 40 minutes, so decided to lump half of my winnings on red, and lost
. I withdrew the deposit and remaining £60 profit. Fairly good for just under an hour's 'work' whilst waiting for the tennis to start!
PS, the offer does sound too good to be true, so if you're a bit cautious, don't do it straight away. I withdrew via neteller, so as soon as any winnings come through, I'll let you know so that everyone can take advantage of this offer!!