We have it on good authority and from a number of sources that Guy Henry, better known to international audiences as Pius Thicknesse in the final two entries in the Harry Potter series and here in the UK as surgeon Henrik Hanssen in the popular BBC series Holby City is a member of the cast of Rogue One.
They go onto say that they believe Guy Henry plays an Imperial officer in Rogue One.
Guy Henry is probably best known to the average Star Wars fan like myself as Pius Thicknesse in the final two Harry Potter films, and from Rome and the John Adams miniseries. You can see his full listing here on IMDb.
I missed more casting news at Jedi News:
Bern Collaco: Landing Crew/Stormtrooper
Angus Cook: Mechanic
Nabilah Karim: Samurai