Hufty, I've just completed the CPL (H) and while I'm sure there are individuals who've done the flying course on a weekends only basis I can't imagine that is a very satisfactory way of doing things. Unlike the fixed wing world helo pilots don't require an IR as standard so I haven't crossed that obstacle yet but by all accounts the IR course is very intensive and therefore I would imagine that it is very difficult to do this in bits and bobs, as and when.
As you know this game is all about personal sacrifice after personal sacrifice. Bite the bullet (again), take the time off work and good luck.