My tables are expandable - normally, it's a smallish table for 4 people, but it can be made longer to accomodate more. These tables easily fit into a standard one-bedroom flat.
Given that the typical one bed flat has a single room that isn't bedroom, bathroom or kitchen (although actually, many modern builds seem to be not actually have such a room - it's just a living room with a cooking area up against one wall), do you move everything else out of the room with the table in? I'd probably have to move the sofa out, and a cabinet, so I could drag the table into the middle of the room so people could sit all around it, and I certainly don't have eight chairs to put around the table. It would seem like quite a waste of space to have so many extra chairs in the flat permanently just for the occasional dinner party. Where do they go when the table is contracted into four-spaces mode? Or do you borrow some? I do know people who've borrowed furniture for a particular event.
TLDR: it's not ideal, but doable.
Chairs, of course, were assembled from various other uses around the apt, and I had a few slight, almost space-less lawn chairs if I needed extra. In my smallest apartment, I'd pull the door against the couch, so that three people could sit down. But this was obviously not ideal because they sunk much lower...
I don't know where you live, but I guarantee you could find a large apartment or duplex or something to rent with a few friends, which would be cheaper than living alone and give you more space than you know what to do with. As an added bonus, you'd have a few reliable guests to seed your dinner parties.
Central London rental property is beyond ridiculous [1] (that's partly why I left). If you choose to live there, it's unreasonable to compare it to anywhere else -- except Hong Kong, Singapore, etc.
[1] https://www.gumtree.com/p/property-to-rent/nice-single-studi...