Thank you all. Appreciate the comments.
Good and bad news for this update...
Markings are applied to upper wing and will be left to dry before I can add some paint around the edges as per coplour profile. I've also added some shading to the lower wings using the usual Tamiya Smoke X19....

Now some bad news. I noticed today that the decal on the upper fuselage is lifting. I tried some decal solution on it and a hairdruer and it seemed to fix the issue - for a bout 5 minutes before it started to lift again....

Bugger. Not the end of the world, but a real nuisance

I expect that the surface wasn't prepped properly or had some contaminant which is preventing the decal from adhering properly.
So, I have a couple of options. Remove the offending piece and use another from the W.29 kit I have in the stash (which I'm not planning on using hex camo for). Or, remove ALL the hex camo from the kit and use some faded camo I have from Aviattica.
Any suggestions as to how best to remove decals?
Gary