MightyGem,
The reference you need is CAP493 Section 1, Chapter 3, Page 12, Para 9.6. (Google it.)
I work at the Scottish airport with all the helicopters (!) and basically it is a mandatory requirement that departure wake turbulence is applied by ATC. The lateral distance you mention of 100m is nowhere near enough. You need to be displaced by 760m or more. If you are arriving as VFR then the spacing given to you by ATC is only advisory.
At my unit we are fully aware that helis do not feel the effects of wake turbulence as much as fixed wing but as no one has done any definitive research to prove this then the CAA line is that the above reference is to be applied.
Wish your CP good luck but I wouldn't hold your breath. If you do get anywhere please let us know though!
Regards, ADIS