Chuck Street adapts to what you want to do, and the amount of flying you do with him.
Some PPLs are happy to do a few trips just flying around getting cheap turbine time in a different environment, wonderful scenery, great sightseeing and, best of all, the freedom of flying under sensible FAA regs without all the restrictions the CAA imposes in the UK.
But, if you show you can fly a B206 and want to do more than sightseeing, he'll adapt. Pinnacle landings, confined area, rooftop helipads etc.
Do the CAA allow the hours?
Sensible advice already given, so I won't repeat it.
I've not heard of anyone whose hours with either of the ENG operators in LA have been disallowed by the CAA. Doesn't mean it hasn't happened, but I've not heard.
Is it useful time?
Matter of opinion. I think it is. Why not try it for a week and decide for yourself?
But, plan ahead. They are both usually heavily booked.