Mirroring no claims with different insurers

[niggtv]

I'm thinking of buying a cheap (economical/practical) runabout as a second car, but am not sure whether I can use my 12 years no claims bonus on this, as I'm already insured on my main car. I know there are some insurers that will mirror NCB if you insure both cars with them (Admiral does I think) but does anyone know of insurers that will take into account a NCB when it's already "being used" on another policy? It makes no sense that I would only be safe in one of my cars!

Thanks in advance and apologies for dull email!