For a start it would not be a charter of the 355 it would be a lease. This is possible but you need to know the rules. On this site you will be swamped by jobsworths saying you cannot do anything !! Most of the flying in this country is now done as private including as far as i am aware, even all of netjets, flexjet etc If they were all just mates of yours it would certainly be legal to lease and maybe fly it yourself , if you are taking business clients there could be an argument that there is a benefit, although i have never heard of anyone being taken to court on it. We have covered this before and hundreds of companies are out there still doing lease work in helicopters, planes and jets and it is ridiculous to suggest that they care less about safety.