sorry late reply Colin, been busy with daughter and son-in-law visiting.
I don't use an airbrush (to spray varnish/laquer) so i use cheap hairspray on some models to give a finish for the decals, i suppose i could handbrush "klear" but at 30p a can the hairspray is better for me and gives a better finish in my opinion.
at the end of the day hairspray is just an acrylic laquer, all be it with a bit of a smell