OK, here's the update.
I'm going tomorrow. All fine. I hope my pp show that I was 100% mea culpa about getting very riled and knowing I was potentially making a mountain out of a molehill. If I was on my high horse I did want a way down.
Of course, too, I was most of all cross at myself. I wouldn't call myself a people pleaser. In a way that's what tripped me up because I was on the back foot.
For clarity this is certainly not a group holiday and perhaps the distinction might seem a fine one but it is a retreat, with prayer if you want it and plenty of solitude and some support. I had told the woman in the room next to me about my plans. I went to get food and came back and she was telling this man about when she had been to this town and seen the frescoes. (It is the main destination from here). Most residents go at some point. This is where he jumped in.
Did I think he fancied me, yes, sure, I did to be honest. Did I think he was Hannibal Lector or a sleaze bag - no. I didn't think he'd make a pass, just that he would take my time because it suited him. Also that he was treating the place like an adult summer camp. For instance he was asking for my neighbour's number so he could text her 'if she was up' and they could watch the presidential debate together (at 3am? On a retreat! She's American, was the link) .
Anyway, this morning I thought, OK, he may think we're just sharing a car; if he doesn't I can quickly disabuse him. I said good morning, he said, 'So have you decided what we are going to see?' Me: Oh, no, this is a solo day out for me. I don't enjoy looking at art with other people. I may only go to a couple of places anyway, it's so hot.' Him: 'Well let's chose a couple that we'll each see and we can talk about them over lunch.' Me: No, as I say, I want to spend today alone. Him, shrug. We get in the car, drive to the station. The driver says What time am I picking you up? Me: Well, it may be separately. (We both have his number). Him: well maybe we could swap numbers so we can coordinate a time to get the train back. Me: Oh that sounds like a faff, I won't enjoy being on the clock. Why don't you go today and I'll go tomorrow. This heat looks too much for me already.
Mild consternation, and felt a bit silly getting driven back but - enough. So - here I am.
Thank you for the understanding replies. To repeat, I knew I was reacting possibly OTT; It's sorted, he was a mild annoyance and I should have nipped it in the bud but the bud is nipped now.