While doing my oil tank cap mod, I happened to notice that the oil level was down to the minimum. This was a surprise since on every previous occasion it has been indicating full.
So I removed the crankcase sump plug and, sure enough, out it came - I'd guess about a litre and a half.
Maybe it has always leaked and I have not noticed before, but this seems a lot of leakage to me. The car had been standing for only about 10 days.

Any views?