anyone got any ideas what an old milling machine bed could be used for its 3 feet long and weighs around 50kg ,thought about putting anvil on top of it ,would this work or best of sticking to a tree stump ,

Its a good table to clamp tooling to for making repeat bends or other forming operations.  It's usefulness would be wasted as a anvil base

cheers will have to let my imagination run wild and see what i can come up with 

I agree that it'd be wasted as an anvil base.

Machine tables are absoluty great for tooling tables. great as weld fixture tables, weld fit up etc. Metal planning tables are often available and are usually a very useful size as well.