I asked CATS and they said that option is only available to people with 500 hours multi-crew?
How can a CPL holder have MP time?
Read the ref given by ifitaint
These arrangements provide a route to a UK CAA-issued Part-FCL CPL (A) or (H) , IR(A)
or (H) and/or Flight Instructor Certificates (A) or (H), qualification for the holders of a
current and valid ICAO CPL (A) or (H), IR(A) or (H) and/or ICAO Flight Instructor Rating
(A) or (H), as applicable, issued in accordance with ICAO Annex 1.