If you've only replaced the master cylinder, then I would have thought that most of the air will be at the 'top', and it should bubble back up. When I changed my Land Rover clutch master cylinder, I didn't bleed anything, and it seemed to sort itself out.
As the system is sealed, and the fluid doesn't circulate, then no air should make it down to the calipers (I would have thought). You could probably do with getting the nipples sorted sometime soon though, as the fluid takes on water over time, and will gradually corrode your caliper internals. I sent mine off to these people, and they sorted out some seized nipples and refurbed them:
http://www.brakecaliperspecialists.uk/These people are meant to be good too:
http://www.biggred.co.uk/