Thank you for the advice,
I spent many hours on the internet looking for legal advice to see if they can take a minor to court and haven't found anything to say they will & win the case. I sent them a recorded letter advising that I have discovered my son had signed up to their t&c's and that he was not 18 only 16 and given his age the contract is invalid.
I advised he has no means of settling the spiralling costs and if they didn't respond by 21st August I will take it the contract is cancelled, but I have had no response to my letter. I also asked them to deal with me directly, not my son as he is 16 years of age but they still continued to text my son which I have not got him to block the number. Like I said above my son received a letter today threating to take him to court if he doesn't pay £288 within 7 days.
I accept my son is in the wrong signing up to these t&c's and he has been dealt with by us, but the fact is he doesn't have the money to pay this nor do we.