Thank you everybody for your replies. I used to think he didn't like textures etc as it's only recently he's started eating the chunkier purées but he's happy eating whole foods like toast, pieces of fruit (ones he used to like!) biscuits etc so I don't really have any concerns about that. I also don't think it's an anxiety type issue, I think he's just a fussy beast and stubborn. I do normally eat with him, mostly out of convenience so I will always have my breakfast and lunch with him whilst feeding him. I have tried offering him some of mine but he's just not at all interested.
I'm just going to try and stop worrying as I really feel like I have tried so hard and I'm not just an awful parent who gives him crap as I can't be bothered to make anything. I'm just a bit sick of the waste at the moment as he's turning his nose up at things he used to like. I'm going to stick with being strict but not in an excessive way, ie I will give him a yogurt or fruit purée even if he won't eat his dinner, but I'm not giving in and giving him snacks or sweet things. I'm sure he will grow out of it and like other posters have said, I was also very fussy as a child so maybe it's genetic! We try and make feeding fun, he really enjoys using fork and spoon so we will give him foods he can feed himself when possible although it often ends with him playing and not actually eating anything!