So I removed the gas bottles and all of the bricks that made up the ballast and built the bed for the gas bottles to sit on and eventually go to the bottom of things. In a way it is a good job that I did because if it had been left much longer it would have been a very severe rusting problem.
With the gas bottle locker now completely empty I could see that the vent was about two-and-a-half inches up from the bottom. I removed as much of the loose rust as possible. The locker was (fortunately) absolutely dry, so I painted it with a very generous layer of 'boat blacking' and left it to dry.
The nest day I went to B&Q in Coventry to buy some sand and pre-mixed concrete. The sand was laid on top of the (almost) dry boat blacking and the concrete poured over the sand and smoothed down to make a reasonably level top with a drain-way to the drain-hole.
|A nice peaceful place to work|
|A layer of concrete setting in the bottom of the gas locker|
|Rust removed and treated|
|A grey-sided Constance|