Well - no surprise but painting in the dark is not a good idea... Quite a bit needed to be redone. Also at the end of the session I had painted the "quick and easy" rear foot wells (mostly holes) to see a bit more progress the next morning but that then prevented me getting in the car to do the back seat until it had fully hardened: a couple of extra days on the elapsed time.
I was proper grumpy thinking the weather had turned and it would soon be the kids holidays and I wouldn't get time and it would end up being left just as primer but I found a couple of weather windows and have a coat of gloss right over. I'd like a second coat but it no longer worries me being left.
The primer:
http://dulux.trade-decorating.co.uk/products/info/dulux_trade_metalshield_quick_drying_metal_primer.jspThe first time I used it was on aluminium and it worked a treat. The data sheet says its zinc phosphate in acrylic so it should do the electrolytic thing to prevent rust. I applied it over two coats of Fertan rust converter.
http://www.fertan.co.uk/Item-Fertan%20rust%20converter.htmThe tip from Fertan (great helpline) I hadn't followed (too late by the time I called) was to panel wipe (the worry being the wire brush had embedded grease in the pores). The tip I DID follow was to spray the surface to reactivate in case it had dried too quick in the heat (a couple of spots) and then to wash the surface before primer. I used plain water and a dishcloth.
The gloss is Dulux trade interior. Their helpline is excellent as well. I'd previously used the exterior grade on metal but their advice was that I don't need all the noxious chemicals that exterior wood benefits from and would prefer scratch resistance to flexibility. I didn't use their Metalshield gloss as I can't get it colour matched. Reading the info in the link below it says it CAN be tinted...it also says only four standard colours where I have a card with about thirty. NEXT time eh?

Either of these:
http://dulux.trade-decorating.co.uk/products/info/dulux_trade_metalshield_gloss_finish.jsphttp://dulux.trade-decorating.co.uk/products/info/dulux_trade_high_gloss.jspThis is ok but not as hard:
http://dulux.trade-decorating.co.uk/products/info/dulux_trade_weathershield_exterior_high_gloss.jspAnther primer I like is Bilt Hamber Electrox:
http://www.bilthamber.com/electroxSolvent based but quick drying and the brush can be left in water for weeks if working "little and often". I had intended to use this over fresh brushed steel but I didn't get what I thought was enough clean to make a start before the first bit went orange again. At the time I thought I couldn't get the benefit of electrox over Fertan but I now know that not to be true. I've used Dulux over Electrox and that works well as well.
Just to add some more confusion to the options Dulux also do solvent based Zinc Phosphate primer for steel of which I have no experience:
http://dulux.trade-decorating.co.uk/products/info/dulux_trade_metalshield_zinc_phosphate_primer.jspFor clean up they mention Hammerite thinners which is a clue

Next time? I like the Fertan, a lovely smell as much as anything. I'm hard pressed to choose between the quick drying Dulux primer and the Bilt Hamber electrox. Dulux goes on a bit better, dries smoother, water based cleanup, can buy it round the corner. Electrox on price and all the magazine test reviews but not against Dulux who have my absolute trust anyway. Can't go wrong with either. For a top coat I might try the Dulux Metalshield but would phone them first to understand the benefits over the interior gloss.
I have photos on the PC and have made a start on the edit but will always prioritise "progress" over "report". At least I'm not making you wait for Viva

On that front first article submitted and second in progress.
David