Injector seal replaced and now oil leak

[Spjonesuk]

I have a 2016 Peugeot partner , I was told that one of the injectors was leaking diesel so they replaced the seals on all injectors, I didn’t see this leak but went with what the garage said. Anyway it has leaked oil ever since, it’s always got oil around the injectors, looks like oil! Could it be from the injectors

[Huskyxantia]

Did they renew the sleeves aswell ?if not it might be getting past them , also if the seats were not cleaned properly after the cooper washers were replaced that to can allow diesel to leak .