Patrick,
To get back to your original point, in the UK, the vast majority of units will not differentiate between aircraft types in that respect.
Some may refer to a helicopter as "helicopter N100ST", but thereafter it's just plain old abbreviated N'0ST".
I've never seen the point in prefixing an aircraft's registration with it's type, if there's any ambiguity, make them use full callsign and that will hopefully solve any difficulty.
I am pleased to read what 2 sheds has written, too many atco's come out of the college's spouting MATS part 1 verbatum combined with their own instructors slant on what's in or out, and it sounds bloody awful.
R/T should be precise and concise, nothing more, nothing less.