After a trip to Argos (the bike specialist, not the branch based catalogue retailer!) in Bristol, I received my Montello back looking better than new. I went for a deep metallic graphite in the end with the period correct white decals with the frame pantographs also picked out in white. All the detailing is exactly the same as it would have left the factory inc the white pin-striping against the chrome and the fork top and rear brake bridge painted with detail - except the decals might not melt off after a few months use!
Thanks for all your comments and suggestions ref paint. I noticed that this colour (or one very similar) was an option in the very late 80s catalogues so I thought I'd try and be faithful to the era, without being a slave to it, and pick something I also personally liked. The couple of pictures I hastily took at the updated link: http://sdrv.ms/Pa5Ab8
don't really do the colour justice, I'll take some better ones when built up.
On the build, I have a C Record groupset to adorn this and I'm fortunate to have both the original aero leavers with down tube shifters and a set of 1st gen Ergos. I'm leaning towards the down tube shifters to keep it more faithful to the period and the other issue is pedals, early clipless or late toe clips! any thoughts?