Mystery switch

[Bowline5]

I just bought a 57 plate Forester and boy am I pleased with it. I had one of the first cars in the country back in 1978 and after all these years have come back to the badge. Below the steering wheel there is a round red rocker switch, I haven't found a reference to it in the owners manual yet and don't want to press it just in case. Can anyone give me a clue what it's for please?

[Greenmamba]

Photo would help identifying it but it does sound aftermarket.

[Bowline5]

I spoke with a dealer today about something else, turns out it's for the front parking sensors.