Sorry to hear of your troubles mate.
Italy has been, and still is, the best source of used XT660 motors in Europe. They are much cheaper than UK sourced ones, tend to have done a lot less Km and the lacquer doesn't suffer so much from the UK's heavily salted roads, plus of course - Italy is a lot closer to Austria for shipping (or collecting)!
There is one on ebay.it at the moment with 7,800Km on it for EUR600.
http://www.ebay.it/itm/YAMAHA-XT-660-R-ANNO-04-16-MOTORE-COMPLETO-COMPLETE-ENGINE-7-800-KM-/262837115365