That depends where you are travelling in the UK. The Siemens Desiro is used around the Midlands, on the Transpennine Express and some routes out of St Pancras and Waterloo, but is also widespread in Belgium, Austria and of course Germany ( all with fairly good bike access). Eurostar's Siemens Velaro is also Germany's ICE3 and some of Spain's high speed trains (all with pretty poor bike access).
The rules may differ, but they differ between UK operators. The on train accommodation is rarely unique to the UK. I'd say keep train discussion across Europe as one.