Thanks for all the advise. It was all very worthwhile. When I stated I wanted my purchase to be an investment I meant it should ideally not lose much value in the long term and might appreciate. I accept that there are better ways of making money and fashions and demands change over time. I would envisage passing on my collection to my sons.
I'm thinking of buying a vintage gold Jaeger le Coultre Mastercontrol Geographic mainly because its a classic looking watch and Jaeger is an acclaimed Swiss brand. It is important to me however that a watch purchase be an investment. Any views on same?