Yep, all sounds familiar stuff.
I'm in exactly the same boat as you, and off to Tayflite in Perth to renew the IR in their multi sim. £100 ph +VAT and £150 for the test. Seems pretty much the norm.
I couldn't get a straight answer out of anyone I spoke to except these guys. The upshot of it seems to be this;
CAA would prefer you to renew a multi IR in the air and to have a MEP, but it is not compulsory. You can renew just the multi IR in a sim (much cheaper) without any need for a MEP.
Obviously, if you're trying to sneek into the airlines too, then neither the IR or the MEP would be much use as you would subsequently end up with a multi-crew IR which is different again. However, nice to have what you can on the licence (especially a multi IR) as it helps avoid being the first CV chucked in the bin.
