Bmw 1 series 116i petrol (2008) - Oil leak

[vinchau9]

I have a 116 (E87) and have noticed what appears to be an oil leak coming from the side of the engine. I've attached a picture (link below). The area below the rocker cover looks dry but not sure where the source of this leak is coming from.
Wondering where it could be coming from if anyone has had a similar experience.
Any comments much appreciated.

https://1drv.ms/i/s!AnDh9pstIZFEhjUW...wvIob?e=0VKKN9