I just have to sing the praises of a great product called "Mr McKenick Electronic Contact Cleaner". I have used it on all sorts of jobs - tow hitch connectors, electric seat switches on my old LR Disco and now on a non-fucntioning TR7 light switch. On Saturday only the sidelight would come on - the lamps wouldnt lift and wouldnt light - the flash switch lit the lamps but didnt lift them.
I removed the switch, took off the cover and sprayed copius amounts of the cleaner into the contacts. Today the lamps are working normally.
I will still fir a new switch, but now I can keep the old one as an emergency standby.
On a different subject - I changed the stering column bush on Sunday. The "old" bush was a piece of radiator hose held in place with two jubliee clips. Nice easy job - I boiled the new bush for ten minutes and it just slipped in.
Still standing !