If you really love that frame you can get it repaired. Lugged steel, as far as I know, is relatively easy to repair. See how much it would cost to have a frame builder in your area to put in a new top and down tube. Is reynolds 531 even available anymore? It sounds like your frame was a lot nicer than my 531 frame but it still is a nice ride. I hate hearing about nice old frames going out like that, although it is better for them than slowly rusting away upside down in a garage somewhere.