sudden oil leak

[Will UK]

Hi gents.

I have a problem with an engine oil leak from around the turbo area. Its pd105 vw touran. Its not a sump... there was about a litre of oil under the car in the morning. So i drove to the garage which is just a 5 mins away and they said they will investigate. Refurbished turbo was fitted by them a month ago and everything was fine, oil level wasnt dropping, no whistling, i was very pleased.

What could cause sudden oil loose over night? I dont want them telling me i need another turbo or something...is there an oil separator on those engines? had a look around oil filter housing and its all dry there.

Any help appreciated

Thanks