From memory, the UKBR22 rules define five classes for bench rest. Two of them are for 6fpe rifles, the other three are for 12 fpe and one of them is basically an open class with no restriction on rifle type or scope mag, other than ( I think) a weight limit of 15lb.
Their comps can be shot indoors - in which case you get 20 mins for 25 shots - or outdoors with a 30 minute time limit. 25 yards or metres. Indoors and outdoors are not separate disciplines or classes, they are lumped together.