Naturally I thought the worst when I saw this mess this morning.
I sent these pics through to John Fowler and he mentioned the splatter marks look like they went all the way round the wheel arch which doesn't make sense. There is not one drop of oil on the rim or tyre. The marks are very greasy not oily and thin like shock oil.
There is also no oil residue whatsoever on the top of the shaft/seal area. I remember running over something yesterday going through one of the many road works sites in the north here. I was cursing myself for not paying attention.
John has suggested dropping the car firmly from my hydraulic jack and listening carefully for any noise. If the shock is empty it will sound obvious.
I checked further along the car and the stains run along the sill then inside the rear wheel arch wheel there are more splatter marks. So I took the car for a drive and all seems ok for now.
Whatever I ran over it must have had a fair bit of grease in it.... kaaaarnts.