Compression test

[Wafoo]

Had the oil and filter changed last week and after a drive to Kent from South Wales about 240 miles in total the yellow oil light came on, it was pitch black night so just chucked some oil in
In the morning checked and it was just above the bottom
Either the garage messed up or I have a mahoosive leak/burn
Topped up to proper level drove back and level has dropped but not massively
I did a compression test and all cylinders read between min of 190 and max of 200 which seems OK
However cylinders 1, 2 and 3 plugs were sooted up
Any ideas chaps?

 

[GuidoK]

I think the garage changed filter and oil and did not check the oil after starting the engine and letting the oil fill the oil filter housing.
That explains the yellow light.
If the oil is black: probably not a really good oil drain in the first place (although it only takes little old oil to blacken the new oil)

If you have a massive oil leak, you should see it on your driveway eventually or blueish white smoke from your exhaust.
Take a flashlight and see in the engine bay if you already see oil on the engine undertray.

My guess is the first scenario.
Keep checking your oil, clean your plugs with a brush and some brake cleaner and see in a few days/weeks how they look.