I flew with Phillippe of Heliclass at Van Nuys in 2002. H is also a CFI, so I did the conversion with him, and a week of Traffic Watch, mornings and evenings; I think he usually books whole weeks. I did 25 hours plus the conversion, and had no problem with the CAA with the hours...though I suspect you might if you had hundreds of hours! I learned a lot, and it was good fun, but to a certain extent you get what you pay for - no start-ups and shut downs, not that much apart from straight and level flying (though you do other stuff when time), and I think I'd have needed a bit more more training just in start-ups and so on to do the UK B206 conversion - I couldn't afford it so it never came up.