I think I've found out why occassionlly I loose all my header tank / dump loads of water.
Yesterday it did it again, and after some poking around I noticed that the bottom radiatorhose was only just on (end of hose on raised bump)
Checked jubilee clip and is spun around even though it looked tight. It was rusted through.
I pushed the hose back on and have fitted a new jubilee clip today.
Just as well it didn't do it somewhere expensive.
Andrew

Yesterday it did it again, and after some poking around I noticed that the bottom radiatorhose was only just on (end of hose on raised bump)
Checked jubilee clip and is spun around even though it looked tight. It was rusted through.
I pushed the hose back on and have fitted a new jubilee clip today.
Just as well it didn't do it somewhere expensive.
Andrew