Back together and working again!
The old Trek's had an unfortunate time lately with back derailleurs falling to bits causing the hanger to snap and the resulting cycle home on a short chain destroying two of the front chain rings. It looked like an expensive repair job but after I'd bought a new hanger and installed it the natural thriftiness of my nationality came into play. As someone who very rarely throws anything away I have an amazing amount of junk in my garage, but if you look hard enough you can usually find something that'll do a trick! And so it turned out, I found not only one old derailleur but three, admittedly some of them had bits missing but one seemed in reasonable nick. Then I found a middle and outer chain ring of all things, where they came from is anybodies guess and inevitably there was an old chain (or two) to finish the job off. When this lot was all assembled the bike actually went better (touch wood) than it has for some time and survived a fairly stiff test run. Is there a motto to this tale of tight fistedness, probably not, but at least the junk heap's been slightly reduced!