Late last year Dan Starkey confirmed that Sontaran Strax’s revival in The Snowmen would be properly explained.

Starkey explained: “There will be a little Easter Egg thing about that. We recorded a scene between Jenny, Vastra and Strax set two days after the Battle of Demons Run, before they’re taken back to their time zones. I don’t know if it’s going to be a preview online, or a DVD extra or what, but it’s a lovely little scene.”

It turns out that this is a 3-minute mini-episode called The Battle of Demons Run: Two Days Later.

The site description says: “In the aftermath of the battle of Demons Run, a battle-scarred Strax lies dying on the floor – or has he just fainted…”

This is currently available to download for free on Amazon and iTunes (US only).

UPDATE: Link added. Big thanks to Nate for uploading.