Thanks both you have given me some good advice. I will try and answer any questions:
He sleeps 12/13 hours a night and most days doesn't nap. I put him down each day to nap but most times he just amuses himself until I get him an hour later.
He has never been checked for tongue tie but I had to give up bf after 4 days as it was so painful. I don't know if it's the same as tongue tie but where the top of his lip attaches to his gums there is no gap between the teeth and the flap (don't think I'm describing that very well) but my mouth there is a gap between teeth and lip flap thing 
He had his hearing checked at by HV when a baby. I am pretty sure his hearing is fine, although he does sometimes take a few attempts to get him to notice me but I think he is just concentrating on other things.
We do watch CBeebies for around 1/2 hours a day and he does try and sign along to Mr Tumble and some others so I think I will look into sign language.
He mixes with other children well, but does not get a lot of chance to mix with children his own age, mostly older cousins who are 5/6.
I have tried reading him stories before bed but he never seems interested and will just pull the book/rip pages. But I could maybe think about books on tapes if you think that could work just as well?
I think I need to cut down on tv time and am going to start with that tomorrow.
He doesn't snore unless he has a particularly bad cold.
I talk to him a lot through the day, as a single mother he is the only conversation I get some days. I usually give a running commentary of what we are doing. Ask him questions and always give him choices, trying to get him to repeat after me but he very rarely does.