Reverse switch location?

I don't have either reverse light and the connections behind my bumper seem good.  Where is the switch on the automatic transmission so I can check it?  Many thanks. 

Panic averted. It was both bulbs simultaneously or rather I only noticed them both now only could have been gone a while!

So after some but not exhaustive research it seems that there isn't a switch as such but that it's part of the operational process of the range sensor and is determined via continuity across certain terminals. So as long as the dash is saying what gear you are in then that part is working and you would be looking at wire condition and plugs etc.

A further point of enquiry. On the auto every time you go from park to any other gear you have to go through reverse and so are momentarily flicking the reverse light on potentially many times a day for only a few tenths of a second each time. This cannot be good for an incandescent bulb, would an led fair better?

My experience with LED automotive replacement lamps is they don't last any longer before issues appear. You tend to get partial failure, LED groups within the lamp will start to fail over time, IE they get dimmer or just stop working. Considering the cheap cost and how long normal incandescent lamps can last LED alternatives aren't cost effective in my opinion. If you like the LED look then that's a different question, fit away and enjoy.

On paper LED should last longer, but poorly designed over stressed LED lamps are in abundance in the market place. Yes, like all devices, switching frequency will shorten all semiconductor devices life span, but to what extent will depend on the design.