sorry madmark, i forgot u asked about her, yes i still have her and am a twinwheel fan, with a mk1, 2 mk 2's and 4 mk 3's! The yellow mk 2 needs a fair bit of work but nothing a good migwelder couldn't sort out. i am studying away from home and have no access to pics at the mo but as soon as i'm back i'll post the lot.
I know about the difference between mk 1/2 and mk 3 twin wheel axles as we had a mk 3 and swopped the axle with one from a mk 1 ambulance, the wheels were just flush with the body on both sides and looked well. Don't know about your one with 1 set of wheels poking out
The easiest way i can explain it is if you take a look at the wheels on 100ps_drw_hicube's van (which is quite nice!), they are the ones i want to change to, and will def not be a straight swop onto my wagon.