Back in the day when there was a glut of td5 bulkheads on the market, they were also offered newly galvanised.
Think I read somewhere that some place builds bulkheads from scratch using all the repair sections you can buy and filling in the rest. I don't fancy the price of that one though.
As suggested a reapired bulkhead then galvanised might be the cheapest option and if you need the vehicle buy another one and do a swap.