The obvious question is, "How much do I have to wager?" and that's also pretty reasonable - at just 12x the deposit plus bonus amount a £10 deposit gives you £42 to play with and a total of £504 worth of bets you need to make before you are eligible to request a withdrawal. You could be forgiven for wondering what the catch is, and you'd be right to do so! This isn't a cashable bonus, meaning once you have completed the wagering requirements it will be removed from your bonus prior to you being able to make any withdrawal. You can keep on wagering if you wish to try and get your balance as high as possible before requesting such a withdrawal, but you might regret that if it all goes wrong and you finish up losing the lot after you have beaten the initial wagering requirement!
These non cashable bonuses are quite popular with Playtech and Rival casino's, but have largely disappeared from the industry otherwise. Reason being that players just don't like them - you have to put your own money in in order to receive the money, you have to risk your own money as well as the bonus money for a chance at a profit, and then at the end they take it back off you anyway - you have to get REAL lucky in order to end up making a withdrawal and although I've managed it a few times we're talking just a handful over a period of years here.
Even so with the wagering requirement being so low, you might consider this a bonus worth taking for the extra playtime with the possibility of turning a little profit a well.... overall I think this is one that everybody needs to make their own mind up on.