Installation work isn't covered by Ofcom, so forget about them.
Trading Standards won't normally get involved with civil disputes between contractors and customers, so I doubt that you'd get much help there. (All the same, it might be worth a quick phone call to see if they have any observations or suggestions).
Before you could get a court to rule in your favour, you first of all have to give the relevant company a chance to meet your demand for compensation. There are two important points here:
1. You must ensure that you make your claim (and, if necessary, take legal action) against the correct company. If you placed your order by contacting Sky directly, your contract was with them and you obviously need to claim against them. However, if you signed up, say, at an in-store promotion, you might have been entering into a contract with a local 'approved installer' and your claim should be made against the local company, not Sky.
2. You will need to decide whether you wish to make your initial claim against the company yourself (and then only employ the services of a solicitor if the claim fails) or to use a solicitor from the outset.
In the first instance, I'd suggest that you should:
1. Read your contract document very carefully to check which company you actually had a contract with ;
2. Prepare an itemised claim which shows exactly how much you believe that you should receive. (There's no point paying a solicitor, by the hour, to do this because you're the only person who has all of the facts, such as builder's estimates, to hand) ;
3. Visit your local CAB to get some further general advice before you have to start paying for it.
Then, if you are reasonably confident with writing 'official' letters, you might wish to consider writing to the relevant company, outlining your demands and seeking payment. However, if you don't feel confident about drafting