Afraid so totally illegal
http://www.caa.co.uk/docs/175/SECTION%20A.pdf
Appendix F section 2 para G
States same type or CLASS and as MEP is a seperate class to the SEP your where out of the 90 days.
So you should have had 3 takeoff's and landing in the last 90 days on MEP before you could take pax.
MJ