Timing Belt Etc Change, But What About The Other Belts?

[sparkzilla]

Hi

I'm coming to my 80,000 service and still have not had the timing belt changed. i will make sure i get the following changed

TIMING BELT

TIMING BELT TENSIONER

TIMING BELT IDLER

but reading through posts here, people have other belts changed as well, such as air-con belt, power-steering belt and i think i read water pump.

1. Will i be OK just to get the timing belt, tensioner and idler changed, or do i need to be looking at changing all the other belts too and which ones?
   
2. I have been converted to LPG, will this effect the changing of belts?
   
3. Other than Lexus dealerships (£££) are their any suggestions where i can get the work done around Preston area (don't mind traveling a bit)
   

Thanks

Mark