Mmmmmm ....
......In the USA you can do your IFR in an R22 or Jetranger and it is everlasting. Not even a requirement for a specific helicopter bi annual review- do it in a VFR Cessna 150 if you want to......
Dick ... that is just not quite correct ... yes you can get a Helicopter Instrument Rating that stays on your pilot certificate BUT you still HAVE TO MEET THE RECENCY REQUIREMENTS in order to exercise the privileges of that rating ... if you do not maintain the currency then you have to do a flight with a CFII to renew those privileges ... having said that it does seem easier to us here BUT they do have a very much more workable system and it has proved its worth over time.
Cheers