As Whopity says the IMC Rating gives privileges for aeroplanes in general,
not for specific Classes (or Types?)
As a Pilot would achieve the same privileges, irrespective if the IMC Flight Test
was conducted in an SEP or MEP, it does seem incongruous (at least to me)
that the mandatory test items are different depending which aircraft Class
is flown for the actual Test.
Anyone know how/why this arose?
2close
Just to confirm: You must have a valid IMC/IR(R) to fly MEP IFR in the
circumstances you've outlined - your valid SE IR does not count as
an IMC rating.
If you have previously held an IMC rating then the Examiner who
conducted your last IR Test can sign to renew your IMC (as the IR Test
contains all the elements of an IMC Test).
If you have never held an IMC Rating then you would need to apply
to the CAA for an IR(R). Your IR credits you all learning and training
requirements and your last IR Test (provided within last 24 months)
counts as your IMC Test. Basically just a paperwork and fee paying
exercise.
In fact I would recommend the above to all IR holders who have never
held an IMC. You never know what you might want in the future and,
currently, no new IR(R)s will be issued after April 2014.