Hawkesy
Like most aviation businesses, the helicopter charter world is extremely competitive and the initial outlay is normaly pretty huge making the risk not insignificant. That said, there is plenty of business out there even if it may be hard to find initially. Like any business start up, research the market and then research it some more. Do your sums then do them again. If you think you can do it, go for it.
I always find that when everyone tells me I can't do something, it just makes me want to do it more! Good luck if you decide to go for it.
Merlin