Finally had a couple of hours free this afternoon so got the toolkit out again. I started taking the side fairings off so I could get at the screen and discovered
yup, that's right
the front subframe is almost as rusty as the back was.
Everything off, discovering that the front fairing had a few less fixings than Suzuki fit in the factory. Bought some black fittings for the screen (sorry Bib, Probolt) so had enough spare for later. Sorted the rust, slapped on the hammerite, fitted the screen to the centre fairing, put it all back together again. Took it apart again so I could fit the instrument surround which I'd forgotten (doh!) and it's all sorted.
Pics of the finished job once the sun comes out.