I need opinions because I'm pooing myself and considering cancelling 
For a bit of context, I do have quite bad anxiety, so dates in general are pretty stressful, let alone under these circumstances!
I've been on 2 dates with a really lovely guy, both of which he has organised. Date 1 was a coffee and a walk around the park, and date 2 was a couple of drinks in a bar (for which he very nicely booked a table, walked me there from the station and then drove me home afterwards). We are due to go on date 3 tomorrow, and I had previously suggested driving out of London (I would drive) and going for a walk, followed by a pub lunch or something.
However. I tried to discuss it with him the other day and he got all cagey about it, saying he had a plan in mind but that it was a surprise, and then sent a list of instructions like "wear sensible clothing; be ready at 10:30am sharp, etc etc". I was totally freaked out by this and basically forced him to tell me what we were doing, to which he caved and said...
... we're going to Go Ape. He has booked and paid for it.
Now, I know he was being really sweet and just wanted to surprise me with something fun, but I'm just a bit taken aback by being presented with something booked and paid for without having asked me first. My anxiety is through the roof.
The final kicker - I've just looked at the weather forecast and it is going to piss it down all day. We are supposed to be there from 10:30am until 3pm!
He has offered to try and cancel, but if I say yes please do, I'm worried I'll look like a horrible ungrateful cow. Really don't know what to do