Nah the phys needed is very low, 1.5 mile run within 14 mins normally is enough...a few press-ups and sit-ups and that is about it.
I did "selection" a few years ago and it wasn't a bleep test, just a run and they record your time.
However, i wouldn't recommend the OTC if you're serious about learning some skills. It is more of a glorified drinking club with some field trips thrown in, if you're serious about doing it join the local TA section. I had friends who were in the OTC in St Andrews for the whole time they were at St Andrews; they hated the lack of activities. I also left because of this reason. If you really want to become fit join TA Paras - the closest section is in Edinburgh however.