i am looking for a half hour sliding FD for a domestic bedroom approx 720 to 820 wide by 2+ metres -nothing fancy or too expensive - would appreciate your advice - thanks and regards - leo

I am afraid inexpensive sliding fire doors do not exist you will have to pay around £250. I would simple google "Sliding Fire Doors" and do some research.

Are there any sliding doors which are acceptable as fire doors? The doors are to go between a kitchen and entrance hall to provide an escape route for people in the bedroom

Sasha

Yes you can get fully certificated sliding FD30 fire doors simple google "Sliding Fire Doors" and do some research and check out the certification. They are usually designed for 100mm walls but are expensive and not easy to install, I doubt it would be a DIY job.