bizzare diagonal brake failure!

I have a discovery TD5 2002. Whilst replacing the rear brake pads I could not push the Caliper piston back far enough to get the new pads in so I released the bleed nipple which allowed me to push the piston back fully. Now I have no brakes on the primary diagonal. I have removed both diagonal bleed nipples to look for pressure but when the pedal is pressed no fluid (or air comes out). The other diagonal is working fine. I suspect the ABS unit has been confused and is not letting that diagonal brake but how do I unconfuse it. Any body any ideas.

Yes, happened to a friend of mine something quite similar ... new master cylinder was the cure, see this untill the end http://www.landyzone.co.uk/lz/f8/no-brakes-one-side-right-170232.html

Thanks for that info sierrafery. I have however now fixed the problem. I was told to speak to a Keith Elgin at Keith Elgin motors in Edinburgh. A bit of a Land Rover whiz kid. He told me I had confused the ABS brains and it had shut off my primary brake circuit and to try disconnecting the battery for a while. When I reconnected the battery the ABS brains had unscrambled and my brakes are perfect again. Cheapest repair I have ever done. I would not have believed it.