I urgently need to find the variety name of this sunflower.

The centre of the flowerhead (brown part) was about 10cms across. The outer petals around 5cms in length, bright golden yellow, with an orangey tint. These petals quite pointed and with distinctive ridges along the length of them.
The bracts we numerous, very pointed and quite long (5 - 10cms). They were very hairy.

The smaller composite flowers were about 1.5cms long, yellow changing to purple-ish brown at the top. Stamens fused.

I've painted this for the RHS botanical art show in London next week and really need the variety name! Any help is MUCH appreciated!