Despite having owned my Mk 1 S for four and a half years this morning was the first of me realising there is a light (two actually) shines down onto the cup holders ahead of the gear lever. I think that a petrol receipt lying in the holder helped. I also noticed that with my height and seat position, the gear lever knob masks the cupholder so that may partially explain not seeing it.
At first, I thought a bulb had come adrift and was shining down the back of the panel, but all the knobs and buttons were correctly illuminated, and further investigation revealed the two lamps.
As I said, you learn something every day.