There's a list of 'em somewhere! i.e. R22, S300, Enstrom, B47 etc. You have to do a type rating for each but the LPC can be done on the R22 in year 1, the S300 in year 2 etc back to R22 in year 5. Off the top of my head, I have a feeling the R44 may not come into this category but I'm not sure (as I'm not rated for it!)
Here we are from F8.4 LASORS which give the ref for JAR-FCL - Sorry I was wrong about the R22!
F8.4
RE-VALIDATION OF HELICOPTER
TYPE RATINGS
Revalidation of a helicopter type rating requires a
proficiency check in the relevant type of helicopter
within the 3 months immediately preceding the expiry
date of the rating, and at least 2 hours (including the
proficiency check) as pilot of the relevant helicopter
within the validity period of the rating.
For single-engine piston helicopters
as listed below
(Appendix 1 to JAR-FCL 2.245(b)(3) refers), an
applicant shall complete at least the proficiency check
in accordance with JAR-FCL 2.245(b)(1) on one of the
applicable types held provided that the applicant has
fulfilled at least 2 hours pilot-in-command flight time on
the other type(s) during the validity period which that
revalidation proficiency check shall carry across. The
type ratings for this purpose are:-
Bell 47, Brantley B2, Hughes 269, Enstrom ENF2
Cheers
Whirls