Ive paid self employed labourers / learners around the £75 / £80
And I sometimes 'borrow' a labourer from a plasterer I know. Hes a quite a skilled labourer that can run in a bit of brickwork, knock up, fit celetex etc. I pay him £100 / day.
IME you get far more value from an improver than a novice, but anybody half decent is hard to get hold of.