What's even more unlucky is the flat below me (above the basement damaged flat) get their sani flo serviced and look after it from what I can see in their emails.
just top floor (flat 5) and ground floor (flat 2). Essentially all the plumbing is on the RHS of the building as you face it and everyone has a bathroom that side I believe. Those 2 flats carved en suites into a bedroom on the opposite side so needed one (previous owners).
What's even more unlucky is the flat below me (above the basement damaged flat) get their sani flo serviced and look after it from what I can see in their emails.
Top floor flat has one and 100% does not do that.