You can just bypass the switches by hardwiring to the preferred position on the xover, which is what most people seem to do - if you can't find the info on the Hilberink site then join the Tannoy forum on Yahoo, lots of people there have done this.
I cleaned my switches up and replaced all the caps with Wilmslow Audio supercaps, but may get rid of the switches entirely one day.
Like all switches and pots they work best when being used.
No need to switch anything on,just crank them round from end to end a couple of times every month or so and they will last for ever. Don't forget the ones on the amp that you never normally touch very often,things like tone controls if you have then and balance.If you have extra push buttons for switching things in or out give them a few pushes as well.