Anyhow. It was badly rusted out, and the timber was in terrible condition. Years ago it was kinda refurbished with a few replacement timbers, but it's seen a lot of decay since.
So, the other week I completely stripped it down. Timber and metal. Wire brushed down all the steel and resprayed it with a gloss black Engine Enamel. (high temp paint) The timber felt the wrath of my belt sander, and then the goodness of 2 thirsty coats of decking furniture oil.
Unfortunately I don't have any 'before' or 'during' shots. Only 'after'.

The timber previously looked like the deck does now.

It came out great !!!