Hi and thank you for the quick response.

In contrast to my last post, I am now very sure that it is the card. Today, other games are now crashing and the display itself has bluescreen'd frequently with severe discolouration of the second monitor. We are going to RMA the card and try a different one once we can get our hands on it.

I'm not sure what made the card go from perfectly running for about a week to suddenly near-on bricking itself, but at least I have some closure. Will update once another card has been used.