I remember training for the rmr and it was quite difficult to fit round the shifts especially finishing at 2130 and being up at 4,5am for work so chucked it in.
Also bare in mind you'll have to use your own leave allocation for most of the weeks off etc, may be different at other tocs.
Fine if you're single but with family etc its logistically quite difficult.
Must say I loved it though and miss it and would go back in a heartbeat if I wasnt too old lol