I finally finished the frame swap yesterday, after a bit of frigging around with the plastics. The accident/recovery caused some tag & fixing damage but got there in the end. Started after the second whirr of the starter motor & runs through the gears on stands. I'm delighted with the outcome, especially as it was all done in my back garden in the open air. Only left with two, very small screws that should attach the belly pan, but the tags are broken so they've nothing to screw in to. Here's the finished article.