not true you can do a full faa licence in the uk there is a examiner adam house
and lots of instructors aidrian parker yorkshire,ray jones glouster/south wales ,tim price shoreham to name 3 , depends where you are really
or you can go stateside
i do know aidrian parker also has caa md 500 licence and ray jones used to deliver md helicopters for the distributors in the uk
one stumbling block is that you would need DTI approval to PAY your instructor but if its your own machine that should not cause too hard to sort