Owning your own home

Find out who owns it from Land Registry. Approach them. Offer way more than it’s worth and suggest an uplift that pays them again if it ever gets planning.

Whether they’ll go for it depends what they can think of to spend the money on. I have a friend whose neighbours gave him some of their garden for just the cost of the legal fees because they were stressed out by having to maintain it. Similarly if it belongs to someone who owns 2000 acres that have been in their family since the enclosures there may be no price they’d sell at.

Offering to rent it and maintain it might be more successful.

Yup, my mum bought half neighbours wild /woodland land as their partner had died and they weren't interested in maintaining it anymore. Was separate to original neighbour house deeds anyways so easy to do. Price was equivalent to their most recent builders bill for installing new land drains and a sump pump in a basement type area.
Then at the other side of house was some scrub land that formally belonged to her house (300 year old smallholding), was compo purchased by highways to build a bigger road in the 70s,then sat as rough ground ever since. Previous owners and then we've used the land as a veg patch pretty much since mid 80s,so didn't take much to go through the process to officially acquire it back again (for basically fees from crown estates (right name?)), could have bought a near mile long strip between the two roads without much bother, but just claimed back what formally belonged to the small holding, as the rest used to belong to the dozen other small holdings along same road, none of which are interested in it currently. Will never be worth anything and you couldn't even really put up a fence on it as it's adjacent to a trunk road, but for veg and piece of mind the brocoli will be ok, it was worth it.