Section F1.4 page 9 (231 of 608 of the .pdf):
This instructional flight may be replaced by
any proficiency check for a class, instrument or type
rating (or, in the UK, for an IMC rating) with a JAA
qualified examiner.
At least this has been cleaned up a bit in LASORS 2005. It used to be rather vague about exactly what sort of proficiency checks counted.