Interesting, did you re-register the new chassis number?
As for painting galv, if it's fresh it will have salts comming out of it for ages, better to leave it outside for as long as possible then use a primer "designed" for galv. Done quite a bit of galv painting and have had good results with the hammerite water based primer, their new smoothrite paint dosent cover to well though IMHO.
Also used some commercial Coo-Var last week, didn't read the tin well enough as you can only recoat it within four hours of the first coat! What a bloody mess!
Interesting this, just have to wait and see if cousin lets me have the 2A now!