Wow! I did not expect this many replies, thanks a lot everyone. We've started to plan our trip on a map from your tips already. As has been pointed out, I should probably have written some relevant things, so here goes:
-we're from the west coast of Norway, so we're very used to cold, heavy rain and strong wind, probably moreso than you brits

-we're starting and ending the trip in London, although we won't stay there long, as we can easily go there for an extended weekend later, not so for the rest of the country.
-we like history and general attractions, exploration, hiking and general summer activities, pretty scenery and landscapes, as well as meeting new people, and of course, pubs!
We're kind of drawing a blank on the area between the Lake District and Bath though.
I would post the map so far, but I don't have an account for that and I don't think I can just post it directly here. Maybe I could post it on Instagram?
Also, it would be pretty cool to meet some of you while we're there, it's always fun meeting new people, and the people on here are a generally good bunch.
EDIT: Oh, also, I love photography, so I'm gonna take a lot of photos.
Also also, just in case it helps, she's 23, and I'm 25 years old.