Sorry for the epic, I feel that without detail it will be unclear. Feel free to lose patience half way 
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I'm just really confused by this man's signals towards me. I've met him a while ago in a social group, he actually promoted it for me to join as he's one of the organisers. There was instant mutual liking, I feel, I'd say instant attraction but not in a shallow way, not obviously physical for me, but personalities and interests and just general attarction. Since then I've seen him on and off over two years, with some long gaps. He clearly flirted with me in the beginning, lots of eye contact, just looking, very comfortable chats.
I thought I may be potentially interested in dating him, even though he is 15 yrs older but I like him. So I thought I will create opportunities for him asking me out, i.e. being away from the usual group. So I stayed behind after a meeting and joined him for a quick tour of a museum which he said he's going to. All well and lots of chatting/understanding/smiling but all very social, then we went towards the tube and I thought, ideal chance for him to offer a drink/coffee, kind of social and not risking rejection as such if he was shy. Well, again while we walked he kept glancing across to me, but then never offered a drink and we said good buys. I though ok, maybe he lost his nerve. Next time again similar situation, again I arrived and he 9while talking to someone) immediately turned towards the entrance and was giving me a long stare, then involved me in the talk and then abruptly left and I was left with that new person, it looked like he maybe was embarassed by us looking at each other. He then again had a chance to ask me out when no one was around at some point, but didn't! I thought, sod it, he is probably not single (and at his age unlikely to be tbh). So I didn't see him for more than 6 months, felt like I'm making an idiot of myself.
Recently I came along to something where he didn't expect to see me - when I arrived he absolutely beamed and said 'what a nice suroprise', I also beamed at him as I still like him. By no deliberate design, I ended up sitting right next to him for a while, and again sweet exchange of glances, feeling harmonious and as if we belong somehow, bu this was with people present and not obvious to others. After this, I stayed behind with other people (no way I was chasing him again), and he shook everyone's hand when leaving, and mine last, he doesn't usually shake hands with all. Again said it was nice to see me, I replied I'll see him at a place where he works. I was there for a while, and then he came back into the room briefly saying he forgot something (he didn't find it), when he came in, long eye contact with me again. I thought, well that's encouraging maybe he missed me. So I went to where he works, he was on his own. And again - awkwardness and edtachment, whereas he was beaming in a group at me, he wasn't when one to one (not for the first time) and in fact I thought he was a bit rude. I asked him wheter he had time to show me some stuff of mutual interest, or is he too busy, he said actually I do haev things to do now before going home, in a slightly frosty way!! I said sorry, I can have a look by myself, I don't want to impose. So I went on with it, he was doing some letter typing etc, then later he seemed to cheer up and wa sitting acropss the table just pertty much staring at me and not engaging much in conversation, I was chatting away because I was also a bit nervous, but he was responding but not intiating, also he didfn't ask anything personal even after such a long break in contact. But he sort of warned up and at least smiled at a few things I said. Needless to say, no invites for a drink or even offer of a cup of tea.
I mean, WTF? He so obviously stares and shows interest/attarction, and I feel a lot of chemistry there, but I'm too shy to bedirect, though he has no doubt that I like him. I didnt hide it that I was disappointed when he said he wan't coming to the next event.
So either he is so shy that he expects me to be direct (esp with the age gap), or he is not single. But then why on earth is this show of interest and flirting for want of a better word? Why is he demonstrative in a group when they ar not looking, but all reserved and even off hand when it's one to one? If he's not single, why on earth do it if he think nothing could ever happen, he's not an obvious player/tease type. This is a well respected intelligent man. I think a few people in the group twigged that I like him, and possibly same wit him, so they may tell his partner? but he still doesn't seem to hide it too much when others are around. I will repeat that I gave him chances to ask me out and I'm sure he could see what I'm doing at least after the first occasion. Because of this, I ;m not going to lose face completely and ask him myself, just no. For all I know he may enjoy watching/encouraging me to be showing attraction to him but it's all for a laugh/ego boost and I just annoy him when it becomes close to acting on it. I do feel that we genuinely are attracted but could I be wrong? He's sort of quite close to my 'Mr Right' even though age gap isn't ideal, that's why the angst, even though I have dropped it once before and will probably have to again.