Thank you for all the replies everyone. I fully accept (and have tried to work on, beleive me!) that I can be a bit 'backwards at coming forwards'.
With this situation, as I've said I knew him before we were lodger/landlord, we got along, I will be honest I did find him a tad odd, but odd not in a sinister way. More in the way that he was always very quiet, didn't behave like most blokes, doesn't go to the pub or have many friends.
I missed the post Pyongykipperbang about your boyfriend-he sounds very similar by means of liking plain food and hating anything spicy/garlicy (things I love)! 
but as you've said, your boyfriend acknowledges that it is his issue and knows being rude about it isn't on. Of the mutual pisstaking-yes, I've done (and do!) do that with very close friends/family. But this is very different to that.
He left his last house because, I mentioned to him and others a while that I was going toadvertise for a lodger when I got my new place. I work long hours and the house I walooking at had a spare room, I was a bit worried about money, I knew I'd manage, but haven't lived alone for a while (I was renting in shared accomodation after a relationship break up) so felt it would help.He mentioned that he was struggling renting a 2 bed by himself and didn't have much money or any need for a whole house so he would lodge with me. I thought well better than a complete stranger, I knew him well enough (and had mutual friends who also did and knew him better/and for longer) to know he wasn't a complete creep or really messy or an alcoholic or any other commonly spoken of lodger issues so I agreed.
drspouse nothing-once they'd served our food he just refused to eat it and ate the chips which were further away from the coleslaw. Someone actually took the ramekin of coleslaw from his plate for him but he still wouldn't eat his burger!
Of the age thing I honestly did not consider this. 52 and 38 isn't that much of a gap, so I thought? I thought both fully fledged adults, not comparible to say, 22 and 38 or 18 and 36? But obviously this could be a factor in that he sees (or could be seeing) me as a younger woman and that's the difference.
I have a really keen sense of smell myself and I honestly don't believe anything I cook smells that strongly but we do become noseblind I suppose. I do open windows and the house has scented auto sprays (I've randomly forgotten what theyre called!) and laundry smells and generally is clean.
As I've said in the few years I've known him (and longer that mutual friends have) he hasn't had a partner at all. I dont think he's been booted out by anybody.Not in the last decade or so at least.
violet I should have mentioned in my OP probably but I did actually say something to him, one of the first times he said it, before I realised it would be constant. I said something such as 'I don't comment on your lardy junk food!' or such.
I love the 'ping' comment He does tend to buy ready made microwaveble food or things that need ovening for 20 mins. I couldn't eat that way, I'm too health concious apart from wine but I wouldn't dream of implying that I've a say in another adults food choices.
sparklfairy that's bonkers!
bamechange protective coleslaw circle! (I do like coleslaw)!
greoarious I couldn't stand this. I enjoy my food and it would put me off listening to all that griping.
Nothing puts me off food I love but I agree on that can't stand it. I don't start MN threads about small gripes but I really am bothered by this.
Whenever I showed a prospective new lodger round my house there was always an imaginary person who'd been to look earlier in the evening, who obviously had first dibs... This meant if I just got one of those "this won't work" feelings, I'd created a ready-made excuse. It also meant I could never be forced to make up my mind on the spot, and always had an excuse to sort out details by phone later. this is a very good idea Caradune I'll definitely do this if it comes to it.
I didn't have any niggly feelings really, as I already knew him for a bit first. As I've said he is a tad odd but, I probably am to some people too!
Thank you for the advice, it is appreciated.
greyishdays I agree he did/does seem to find my food choices very strange. He doesn't seem to know much about food at all. He was at the supermarket the other day while I was at work and asked did I want anything. I requested chilli powder and he didn't know what it was! He was also eating a yogurt the other day and said 'Look at me eating yogurt like a vegan!' 
diamnondpony and others I do wonder if he has autism. He seems to have many traits but I Am not a psychiatrist. Food shaming is a thing it seems. But he isnt a child and should know this is rude-children know It's rude!
Of those saying I could slip back into an ED, yes. I'm much better than I was, but I still eat in my car at work and am self concious going out for meals. I like to eat healthily and exercise a fair bit, but I no longer control my food intake like I used to. I suppose I could slip though with food shaming occuring.
rainingbatsandfrogs yes, he does seem to have food phobic tendencies definitely. He told me recently that when he was a child, his parents would have brown sauce/tomato ketchup on their food and it knocked him sick.
curious very good points made. I will see what It's like now I have had a word.
Cam77 about the bantering thing-possibly. He seems to constantly jibe about things/whinge about stuff, I think it is just for something to say sometimes. Maybe it would have been easier to get a stranger.
billy maybe I should have known!
owlone yes, I mean bins aren't supposed to smell nice are they?
terrifiedandworried I could try the having a word with him thing-if I do I'll report back!
I have to go to work now will respond again later!