Slim chance but has anyone ever done this repair to the resistor card on a micra?

http://www.micra.org.uk/threads/k11-heater-resistor-card.41525/

Is it difficult?

Do as "Scott" describes in the link, except that I'd use "Servisol" rather than carb cleaner to clean the resistor card after sanding..

It works better if you get a thick piece of copper wire about 1cm longer than the gap and then solder it in place along its whole length.

It works better if you get a thick piece of copper wire about 1cm longer than the gap and then solder it in place along its whole length.

That's starting to get more technical in its application.

I haven't had it out yet to check if it is fixable. Not quite sure how this card can rust like that.

It's not just corrosion like you'd get on bodies and mechanicals; there's heat involved too, and possibly "burning" of the resistor tracks on the board.