Thought about the bare metal, lacquer thing on my own trike, but we're definitely going with the tractor theme -so there!
Found some for sale on Ebay! £12.67 per litre.
"Genuine Massey Ferguson Vintage Ferguson Grey paint suitable for Ferguson TE20.
1 Litre tin covers 8 -10 square metres, can be brushed, rolled , or sprayed. Can be thinned with universal thinners. Other Massey Ferguson colours available."
Gloss grey, not matt like primer & a bit darker than this photo shows.