Baz, I didn't mean a ten minute rest break, I meant ten minutes away from driving to refuel, unload or do other duties. I shouldn't have used the word break.
Dean, I find I get more driving time from a digicard, particularly if there are hold ups. It appears to me that the digi tacho reverts to other duties when you have been stationary for between one and two minutes. I guess it keeps clocking up driving time for the rest of the minute you are in plus one whole minute. If you get a good hold up on the M25, of the handbrake on / engine off type, it extends your driving time.
I would be interested to know what the official line is on paper tachos for how long you have to be stopped before it counts as other work.