Thanks both. Looks like you need to get underneath the car and remove the undertray to see the mounts, so I will take it to the dealer I bought it from. I got a one year warranty and mounts are not on the list of exclusions, but some dealers do try to wriggle out of these things.
Will update once I have a solution so that others can benefit. Will also try to video the engine movement.
EDIT: I know a good independent garage, can they claim on the warranty on my behalf, or must it be an official Audi dealer?