CP and FP helis are very different to fly, that's for sure. What made a big difference for me was moving up to a larger heli, the 450 size tend to be twitchy and demand quick reflexes. A 500 is a LOT easier, a 600 even better. Costs get a bit out of hand on the really big stuff, a 500 is a good compromise IMHO.
Flybarless may help too because you can easily adjust the responsiveness. You can even get flybarless controllers with auto-levelling these days, but that's cheating!
Nigel........Your'e not alone, I too found it a bit of a transition going from FP to CCP. The 4ch aspect does not take in account the yaw factors or tail control like 6ch which are critical with CCP........what I found helped was spending a little time on a sim to get the 6ch feel back, then going back to the basics with the 450 (hover, 4 corner, reverse oriantation) at low elevation until the feel became natural again.
The fly-barless systems really do make things much more smoother, even on a 450....since, like JPF said, you can program more leveling control factors (rates, pitch) to be more to your flying skill and taste.
Another thing I have noticed, now that I'm flying quads, going back to a CCP has been less dramatic. I've only flown a 450 and a 500 (both fly-barless) six times since I puchased a quad, but it seemed, at least to me, the transition was natural for some reason. I think it is because with quads, like CCP, you must keep the lift factor (forward and reverse thrust) constant and at higher rpms to smoothly move forward or reversed in order to maintain altitude. On a FP that issue is not as critical. It also requires decent oriantation skills to have complete command of a quad......just like CCP demands when flying nose in or rolling at speed........Just a thought!