Are you sure this Dorking person is a breeder? The red female should have golden or or bright yellow shafting. Page 97 of the APA Standard. Picture on pg 110 showing the shafting. Shafting is a fault on many breeds, but not this time.
Check the SOP to be sure of the information you receive.....there is a lot of bad info online.
Walt
The breeder that I'm talking about has Silvers. She said that she needs to correct the shafting in her birds. I didn't look at the Red Dorking description, now I see it there.