Technically speaking, you should have stopped promoting them back at the start of September when the 2005 Gambling Act came in. It’s up to you, if you think the risk is worth taking then carry on and hope nothing happens, or the casino you’re promoting moves to a white listed area for its licensing. Having spoken to the people who do the advertising enforcement, they would contact you to stop first if an issue was made, and the company you’re promoting would be first in line for legal action, then possibly yourself.
However, this would mean people would need to be making a complaint against you first, and so far I’ve not seen any examples of how this white list has been policed. Personally I decided to avoid pushing non-listed sites back in August – but if you have one that’s earning you a crust, I understand the dilemma.