Don't expect fixed wing flying to help you out much when it comes to hleicopters - completely different, although general air experience, rules and regs, nav, met etc will help. Its going to be very expensive - if you get a month off it would be cheaper to go to the US - about half the price. You might be able to do a JAA PPL(H) there but I wouldn't bother - get an FAA one (JAA is restricted to type but FAA lets you fly anything under 12,500lbs)
Cheaper to get (FAA has no license issue fees), cheaper to maintain (fly with a CFI every 24months and you're good to go) and its perfectly valid in the UK.