Hi all, this has self-seeded and occasionally comes up in my veg plot. It's a bee magnet and very pretty so I'd like to put a name to it. About 2ft tall with leaves between 2 and 4 inches which smell a bit like liquorice when rubbed.
Thanks for the hint Borderline, a google search seems to indicate it is Agastache rugosa aka Korean mint which is a short-lived perennial in lighter soils. I'll be saving the seed and growing it in my borders next year. I might use it to replace the nepeta which flops all over the place and needs too much support.