I suppose it depends on how cold it is to start with, how long you run the engine whilst clearing the windows, what sort of journey it is (pootling around estate roads or on a main road) and suchlike things. But the TD5 is a fairly big lump, so whatever, it's going to take a while for it to warm up.
You could buy one of those blow heaters that plug into the cigar lighter and give instant heat, I suppose. Or rig up a remote engine start so it warms up while you're still scoffing breakfast. I bet someone on here has done that. Probably more trouble than it's worth though for most people.