Custard (£2.50 sign up bonus):

Custard is owned by the same people as Cashback Uk, they often also have casino offers although I have found them to be lower paying so check both sites.

However, there is no need to complete levels, you just need to reach £10 to cash out.

I have made £110 with this site.

Rewards Kingdom:

Rewards Kingdom is an amazing site for casino sign up offers. Their offers involve depositing £20-40 and playing it through, meaning gambling the entire deposit amount. The best way to do this is through blackjack, which has a 98% return rate so you will rarely lose more than £5. Once this is done they will pay you equal to the deposit amount, so a £20 deposit = a £20 reward (net £15 if you are unlucky in blackjack). They pay in SC, and 25 = £10 paypal.

I have completed 12 of their offers now and earnt a total of £450 (including any deposit losses).

They also offer other sign up tasks and surveys, they dont pay well but can be useful in meeting the minimum withdrawal (25 SC = £10).

Cashback Uk (£12.50 sign up bonus):

Cashback Uk have a number of casino sign up offers available once you have completed the initial 10 levels. I check here regularly and often see new offers paying £20+ just for a deposit and wager.

I have made £145 with this site.