Thanks for all the responses!
I did see the GP when he initially had sleep issues years ago. Although he was very sympathetic and listened, nothing really came of it.
I actually had a really good chat with him tonight. He opened up to me about his anxieties and although it made his bedtime late, I think it was a great step into him recognising what's causing him the anxiety and I've said to him we can chat every night, just earlier!
Yes AlmostSummer21 he often goes to bed too late but it's not from a lack of us trying to get him to bed earlier. It's been exhausting, nagging him, trying to get him to bed at 9 and then read. He always finds an excuse to come down and get something or go to the loo etc.
I didn't mention he's developed some compulsions. Things like checking things, saying goodnight to me 5 times, he even admitted to going into our bathroom and checking the ceiling and shutting the windows. He's written it all down this evening and put a cross next to non-essential things he does. He's very aware of it and is going to try and cut down.
I'll keep an eye on it. I did have some compulsions at his age, so maybe it's hereditary? Mine never became an issue in my daily life but certaily got worse if I was stressed.
I'll also try the Headspace app, thanks! x