The bit I forgot to add in the last bit.

A little bit of fudging is required, to match coach running heights etc. What I found that I needed to do was to remove the screw from each of the bogie towers and introduce a couple of spacing washers. Now obviously I don't know what washers you will have to hand, so there is an element of adjust to taste on this one. But don't forget to place your chassis alongside another Mk3 coach so that you can see that things line up. I couldn't get it bang on right I ended up about a half to a mil out, but that works for me.