Hi Gareth,
Thank you very much for the reply and the suggestion - so I went Friday noon to one of the two local dealerships, guys were very helpful but also facing this for the first time.
They searched all databases they can access, but the VIN turned out nowhere - seems like they have access to list of cars that were either manufactured for the UK market or already being registered in UK.
At the end they advised me to email Audi UK - which I did and received a quick reply that the document needed is a Certificate of Conformity (CoC) and to email VIN number and full address (seems they mail it) to:
type.approval@vwg.co.uk
I did that too and am now waiting for the reply - will keep you posted.
Best regards,
Ilia.