Thanks to everyone for the comments.
I have made some progress today, even if it's actually put me back to where I was a day or so ago.... I made and fitted the anti-spin strake under the rear fuselage, and I finished blending in the Scarff ring. I then repainted the fuselage, both the PC10 and the grey. I wasn't happy with the grey, I thought it was a little too dark, so it has been redone lighter and I'm much happier with it now.

I will now have to repaint the straps and filler caps on the fuel tanks, but that won't take too long.
I have also made a little progress on the lower wings: ailerons have been separated and pinned, and I have applied .5mm masking tape for the rib detail. I will paint over those quite thickly to lose the edges, then sand down the tapes. That should give me very small, blended in ridges, to give a little shape to the surface.

I also made a new fin and rudder from sheet stock.
I won't be doing the upper wing just yet as I had some problems with removing the ailerons on the lower wing, so I ordered a new micro-saw. I'll wait for that before tackling the upper ailerons.
That's all for today, it's my birthday so I'm going out for dinner!!
Thanks for looking in.
Ian