Ehemmm!
Don't call them choppers in the UK!
You shouldn't have to worry about the flying training bit to much. it shouldn't take you more than 3 months based on fair flying weather. You only have to do some ground exams for the bridge exam bit and then all the flying hours, I reckon you could do with only 135 hrs. but check that for yourself with the CAA. This is in the JAR-FCL world.
Your best bet is either the CAA or the FAA with your questions.
IMHO you should take your employers offer right away, especially if you get paid while training.