I've found no issues with getting bikes on trains in the last couple of years, maybe post-covid no body seems to care anymore? Can't remember the last time I've been asked about reservations (this is mainly with Transport for Wales, GWR and Crosscountry, and a little bit of LNER). GWR always have a couple of spots that you can't reserve. If they're full, there's sometimes some luggage racks in the vestibule that you can fit your bke under (depending on the train). Otherwise just get on and stay with your bike in the vestibule - bit of a faff standing up for the journey but I've never been told to get off by the guard.
I've found no issues with getting bikes on trains in the last couple of years, maybe post-covid no body seems to care anymore? Can't remember the last time I've been asked about reservations (this is mainly with Transport for Wales, GWR and Crosscountry, and a little bit of LNER). GWR always have a couple of spots that you can't reserve. If they're full, there's sometimes some luggage racks in the vestibule that you can fit your bke under (depending on the train). Otherwise just get on and stay with your bike in the vestibule - bit of a faff standing up for the journey but I've never been told to get off by the guard.