A little update.
I've cleaned up the frame, the paintwork was quite dull, so I went over it with some metal polish and after a coat of car wax it's come up nice and shiny. However, it's still a rather peculiar colour. Where there were some stickers and the front mech clamp you can see it was originally a deep purple and it's a shame it's faded because other than that the condition of the paint isn't in too bad. The frame has obviously been stored in strong sunlight for some time and and the pigment is not very light-fast; this is not uncommon with reds and pinks.
I've stripped my Marin and started cleaning up the parts ready to fit to the Chronos frame. Out of curiosity I weighed the Marin frame: 2565g, the Chronos came in at 2235g. Not super light for a steel frame, but 330g, neary 3/4lb, lighter than a Marin Pine Mountain frame. In fact, details of the frame, cable bosses, canti bridge, seat bolt bosses etc. are very similar, the TIG welds are of similar quality and according to stickers on the frames, that look identical, they were both made in Taiwan; I would hazzard a guess that they came from the same factory.