Is anyone able to identify the genus and species of this plant, from the rather close-up shot I've taken of it?

I've posted a picture of it on my website here
http://englishcountrywalks.com/blog/?p=36#flower

Have looked through my copy of the RHS' New Encylopedia of Plants and Flowers, and I think it might be either a Heliopsis or a Rudbeckia, but I'm not sure.

It was growing the beer garden of a pub near the Len valley in Kent.

Thank you for your help -

David