Don’t know about SSSI’s, but when we got ours it was very overgrown with hawthorn and brambles, plus loads of fallen trees. It was impossible to walk a lot of it until it was cleared, and there are some sections that need work, plus brambles keep coming back.
Ours is part ancient woodland part commercial, planted in the early 1950’s (we think), then left. So all the conifers weren’t thinned out and many are starting to die out, but this is good for the log burner!
‘Management’ now consists of cutting up fallen trees, clearing brambles and trying to plant new, native trees.
Don’t forget the cost, apart from the actual land. What’s access like, will you need a 4 wheel drive vehicle? Do you have a chainsaw and PPE? Add training as well.
Still love ours, but just need more time to spend there.