[Richard Coutts-Smith]

Surprised you did not find a few yabbies in the bottom of the radiator as well.
The point you make about the welch plug is a valid one. It's just that you expect them to rot out eventually, while those nice big plates on the "B"'s look so solid, and lets face it, I did'nt know what they were for, until the first one failed. Hence my warning for those new to these beasties. Hmmmm Are there any plates I have'nt mentioned? 'cause that means I don't know about them, and I probably need to...
Rich.