is this ok, loks like manhole cover inside a kitchen

Local school has an inspection cover in the staff room (which is in an extension). When that backs up the drain company has to drag its well-used kit through the school. There is the bonus that one false move with the pressure in the open inspection cover...

At least you'd have a moppable floor

Yeah. I’d run a million miles from that. They could’ve rerouted the sewer / drainage when they built the extension. That they’ve chosen not to is an indication of the impending barrel of bodge-jobs that you’ll discover if you become the owner of this fine abode.

Also, how is that massive space heated? I doubt that radiator would do the job.