take it thats a N/a?
bit gutless (and thats from me witha S3 2 1/4 diesel!!!)
chassis rear cross member, bulkhead, door bottoms (if 1 piece) are usual suspects!
£2100 does seem a tad on the low side, especially if the mileage is correct.
give it a good once over , and of course the test drive - try EVERYTHING