You could do that but you'd be wasting your time.
"Thank you for contacting the Gambling Commission regarding Sky Bet operating as Bonne Terre Limited. From your correspondence we understand that you have some concerns that Sky Bet are still working with advertisements on a third party basis. We must be clear that the regulations governing gambling marketing and advertising are shared between a number of bodies, including the Commission, Ofcom, the Committees of Advertising Practice (CAP), the Advertising Standards Authority (ASA) and the Information Commissioner’s Office (ICO). In order to have some consistency and to avoid confusion, we work with these other bodies on the basis that whereas we lead primarily on the regulation of gambling, other bodies lead on marketing and advertising. In your email you ask us to investigate this more thoroughly.
In this specific case we understand that the decision to close down their affiliate marketing programme was made following an investigation from the Information Commissioner's Office (ICO). Therefore, we would not be able to look into this matter for you. You may wish to contact the ICO and provide them with this information in order to see if they are able to assist you any further. Whilst we appreciate this is frustrating to the affiliates that worked hard to build up an income through this scheme, we must be clear that operators are not required to offer affiliate programmes. The decision Sky Bet took to remove this programme was a business decision made in the best interests of their company and regulatory requirements. We hope this has provided you with clarification. Your enquiry reference is: 1-128527196."
Still awaiting a reply from the ICO. I don't hold out much hope. ASA and Guardian were tweeted repeatedly too. It seems an alleged changing of a tip result wasn't sufficient to warrant further investigation by any of them. None have so far been the slightest bit interested. Additionally, you can't prove FootyAccumulators are knowingly recommending negative expectation tips. Most tipsters genuinely (and wrongly believe) they are offering positive expectation. I suppose you might try to argue in a law court that any tipster should do more due diligence when it comes to a self assessment of their own ability, but typically tipsters will just disclaim all responsibility of losses suffered by their followers. Besides, bookmakers just love advertisers who send them mug punters. That why they close affiliate accounts when you send them winners.