Eeek, I posted an update when I returned last week and only realised it didn't post when I came back to check the thread 
So in summary, the break went fairly well all things considered although it was obviously very different from the reunion/get-together we planned. F1 and her GF did a fair amount of cycling on their own and actually managed to fit some in every day. In fairness most days they got up obscenely early and then joined of us later in the day but the dynamic was Us vs Them which was a shame.
What was odd was that on a couple of occasions they decided to go off and do something on their own and then GF kind of complained that they missed out e.g. one day we all decided to drive to Penzance. F1 & GF chose to do something else. Later that evening in the pub GF kept saying "oh such as shame I missed Penzance, I would have loved to have seen it etc" 
She brought vegan snacks in a wicker basket and kept it safely stashed in the bedroom away from our evil meat 
The weather was wild and windy the first couple of days. They all went out on the 'easy' trek and F2, who admitted to me she was dreading it, fell and injured her foot and the side of her leg so was not
happy at all.
My treks were great and I did one with some randoms I met up with but I enjoyed myself overall.
The driving was fine, it was actually 6 hours rather than 7. I drove the second half of the journey and as we were near the cottage we had to follow several winding country roads. F2 kept saying dramatically "thank GOD I didn't drive, I would have killed us all going around these
bends" so as to emphasize she was doing us a favour by not sharing the driving:)
GF did not pay towards the cottage and I don't know if the petrol money materialized (F2 said there was no sign in her PayPal account as requested). She did bring a vegan chocolate cake..!
I think F1 secretly thought that after watching everyone go off cycling I'd want to learn (she offered again to give me a lesson while we were there!!) but I can honestly say even if I knew how to cycle I wouldn't have joined in on this break. Nothing about it appeals to me!