British trains are narrower than most in Continental Europe, the structure gauge (the width the train can be without crashing into tunnel walls, platforms and so on) is smaller.

For example, a fairly recent British coach is 2.73m wide, but a German ICE is 2.85m wide, and a Danish/Swedish passenger coach is 2.97m wide.

The difference is noticeable.

https://en.wikipedia.org/wiki/Structure_gauge

(Coach widths taken from searching "<Country> railway coach Wikipedia" and finding an infobox with the width.)

Im 180 and never felt a difference in length from my home bed to the sleeper train beds. They may be shorter but not so much that it bothered me. That’s why I assumed they were the same as home beds (standard length in Europe is 200).

Northern Europeans are very tall.