These come up from time to time in London. Typically Victorian houses where the homeowner has converted the cellar into a standalone flat, then rents it out or sells it leasehold.
They have their own front door, but the bins may be stored in front of your window.
One I’ve been looking at has no service charge, and you have direct access to the large garden.
I suppose it could be okay, it depends how well you get on with the home owner who’ll also be your neighbour as well as being the freeholder. There’d be a risk of course if they sold up.
Also being a converted basement it’ll be a bit gloomy. Tolerable if the location makes up for it I suppose, and if you have full access to the garden.
Any thoughts?