Andrew already knew about the ersatz hull plugs on my site. Ray, another T-16 owner here in the USA made them for my vehicle. They are functional but not visually correct. I only have them in locations that are completely under the vehicle so they aren't easy to see even if you try.
The original hull plugs were a Ford part designed for their Deerhound armoured car which wasn't adopted for government contract production. There must be spare plugs out there somewhere but so far they haven't turned up in bulk.
I'm also interested in finding decent condition originals so consider me second in line behind Andrew if any turn up