I'd wager that when that standard was established the divisivility of those metric measurements would not have been a consideration. Most likely it's also close to some even fraction of feet and inches.
This house dates from about 1990 so I think it is built to modern dimensions, but I know nothing about this so I am mostly guessing... the 19cm ish riser also matches an 8’ floor-to-floor height, so it’s a bit hard to tell from just the stairs :-)
2.5m is 8 foot 2.4 inches according to Google (decimals in measurement that are in inches is a thing? I’m metric so don’t know).
The standard ceiling distance between floors must be 8 feet in the U.K..
The joists and surfaces between floors in a home are 12-14 inches thick in total, bringing the distance between the floor and ceiling in each level closer to 7 feet.
The joists go on top of the studs, not between them.
'standard' ceiling height is 2.4m.
I’ve phrased that badly. Obviously the stairs go floor to floor... wall height would obviously be floor to floor minus joists, flooring, ceiling material.