It's very very unlikely, that you'll ever get permission to build a house on woodland ( it has been done though), but , Buying woodland isn't about building a house on it.
You may get permission to , build a barn , build a tool store , build a shelter, build a composting toilet , and maybe even a log cabin.
It's not actually permission, it's just permitted development regs.
We have an old caravan on our woodland, that I would guess has been there since the 1980s . We gave it a refurb , inside and out , put in a solar panel and battery , and it's great ?.