Cyclic is correct as far saying that most of the Bo105s were ex North Sea. I used to operate SPIFR, based offshore and did so for 3 years. Perfectly legal. Yes it could be 'difficult' flying two hours from the platform back to Aberdeen IMC; but we used to do it on a fairly regular basis.
I also spent 18 months flying a 105 on EMS duties. Mainly VFR, but the company I worked for required us to have an IR and to exercise our privileges whenever we could.
I don't fly 105s anymore, but I'm sure cyclic is also correct that the 'grandfather rights' accorded to the 105 expired this year.
bondu