So I actually ran into this today; replaced a lot at my 120k mi service last month, but today noticed a little bit of coolant on the garage floor after the wife pulled out. Once she got back I popped the hood and the bleeder screw was seeping coolant. As soon I touched it to see it if it was loose, it broke off and sent coolant gushing. So my advice is change these with the crossovers as well.
Had to do a good bit of searching but here are some part numbers that work:
-Land Rover - LR031393 - (P/N for the hose piece that comes with a new bleeder), but a google search will bring up a brass screw on amazon, and a plastic one on British Parts of Utah
-Land Rover - LR017802 - same as LR031393
-Auto Zone - Doorman 902-404 (plastic) 902-404HP (brass)
-BMW P/N cross reference - 17111712788 - works at O'Reilly's, amazon, FCP Euro, AutohausAZ