I think that just about answers my question, stay on track, or if you do deviate about 30 degrees would be in the right ball park if its at my own discretion. The reason I should've pointed out was that turns on a procedure are obviously commenced at (x.x)d on the ABC DME or crossing a VOR radial for example, so inaction leads to contravening the instructions set out for the procedure (hence the examination context I put forward). I just wasn't sure what sort of positive action would be appropriate. So long as ATC (and an examiner!!) are happy I'll stick with the track I think.
Thanks again to all that replied