Standard 3MT Tank loco

[Crepello]

I recently acquired a secondhand one of these; as it needed some fettling (actually re-soldering the yellow wire) to get it running, I'm having difficulty re-fitting the body. Despite following the instructions, either the cab roof rises up or the nearside tank won't align with the running plate when the fixing screw is tightened. I've made sure the wires sit properly within the castings. I notice a couple of 'pips' on the lower edge of the casting above the leading drivers but these seem to correspond with depressions in the front of the body tanks, so wouldn't appear to be a factor.

I'd be grateful for any advice. TIA.