Allotments 4 All

I was working at a house last week where the old gardener (81) grew flowers for the house. I took a fancy to one of the dahlias, and he kindly dug one up for me. It's about 4 ft tall. Any idea of a name or shall I just call it "Medwyn's Dahlia"?
(pretty isn't it?)

That's a beauty. What is the diameter of the bloom?

they're about 4 inches across GA.
Medwyn also said that sometimes the colours are reversed (I think that's what he said)