I remember really enjoying 'Mummy on the Orient Express'. Jamie Mathieson was the writer -- I wish he'd come back, but he only seems to have been part of the stable during Moffat-era Who.

Can't believe it's been well over ten years since Capaldi's first episode in DW. The time between then and now feels like it has properties even weirder than a Tardis.

ETA: Mathieson seems to have fallen into a black hole circa 2018. Hope he's okay.