Hi all, I'm also Peterborough based and can only agree that locally we don't have that many places to explore. However, I've found a few places. Connington tower, it's a old ww2 water tower that sits just by the A1. It's about 15 mins drive from city centre. Its relatively high and the view is fantastic.
Another is an underground bunker. I say bunker, but in reality it's a ladder in a set of trees that goes down 15 feet into a room. I believe it was an old nuclear fallout reading station of some sort. I got told they built them all over during the cold war.
It's not far from the city centre at all, you'll need to go down Castor Road, the road that connects Castor to Marholm. It's relatively close to the road, approx 200m. It took me a while to find, so I've been vague with the location for a reason, I hope you enjoy having a good explore looking for it. Let me know how you get on.
I'm not sure if it's been mentioned already but there's an abandoned building in Fengate, next to Activity world. There's you're usual abundance of beer cans and rubbish in there, but it's been abonded for a long time. There was a make shift skate park in there the last time I went in. Worth a visit.
Happy exploring!
Justin