ummmm, 2.6 engine block core plugs?? :/

hi all,iv succesfully got my 2.6 straight 6 going very nicely,fitted fuel lines,got pump working,and then striped and sorted carb probolem,witch im chuffed about! however i put some water in it,and then found water to be ****ing out of the core plug on the side of the engine block,drivers side! are these avalible,or are they a rite pain to get hold of? this is what i feared with this engine!

Looks like part no, 525428. Fits lots of landys.
This might be handy...
pdf Land Rover Manuals | Landroverweb.com

well thankyou very much oxides! i did wonder weather another landy core plug might fit,from a 2.25 or something! its a pain realy,coz she runs realy nice,appart from the exhaust manifold having a crack down the middle,and it gets hot realy quick,becuase it wont hold water! thanks for the input tho,much appriciated!