We happened to be in Sandwich, Kent in the month of September, which was the perfect time to visit the Lutyen's-designed Salutation Gardens. Resident head gardener, Steve Edney, is a dahlia specialist and the garden holds a collection of over 100 varieties, which were on show at the time.
We also discovered a beautiful plant called Bidens Heterophylla, the white flower with yellow centres pictured below, which apparently works well as a cut flower and invasive (in a good way!) in the garden. This was identified for me on instagram by talented gardener and cut flower grower James Horner - who also takes beautiful photographs. So if you see a plant you like in a garden but are unsure of its name, it is worthwhile photographing it and trying to identify this way!