not sure about the multi engine rating, mut i know the MEIR renewal can be done in the sim.
if you passed your test last year you can renew on the sim this year but it has to be in the aircraft the following year. it alternates every year.
if you live in Maidenhead, you may want to try stapleford or biggin hill. i know stapleford to renewals but not sure which outfits are in biggin hill.