Guy - I first saw this technique demo'd at my club. One of our members, Brian, lays Kleer where the decal goes and then floats the decal into it, squeezing the Kleer out using a soft brush. No solvent is used and for most decals it does pull them down into shallow recesses reasonably well. Once dry another layer of Kleer is brushed over to seal it in before that final light coat of matt/semi matt varnish. I have used this method ever since his demo but as said only on small, stencil size, decals. Not sure how it would work on larger areas like the wood work but he uses it on 1/32 scale markings without a problem.
Regards - Tug