Guy Martin
He'd constantly be disappearing off the set only to be found two hours later under one of the on-location vans, stripping the gearbox, having overheard the driver moaning that the syncro on fourth was a bit flaky. Or drinking tea. And he'd insist on flying the tardis at a mental lean, scuffing his knees out the front door.
I really rather like the idea of Sean Pertwee - preferably in Sergeant Wells guise from Dog Soldiers.
"The only people who go looking for Daleks are Kamikazes, glory boys and full-on f*cking f*ckwits."
"Sausages!"
Etc.
Steven R