After some thought, I have decided to name the pekins after Terry Pratchett's witches, because they really look like they are wearing old-fashioned bloomers as they race down the garden! Esme is the black one, because Granny Weatherwax would never wear anything else, and Gytha is the flighty "redhead" ;)
Esme looks to be point-of-lay, judging by her red comb, whereas Gytha is probably a few weeks younger.
Unfortunately the two Essex girls have been rather aggressive towards them, so I have had to buy a small ark to keep them separate. Luckily I was able to get one at very short notice, thanks to a nice local supplier (Adam at Cambridge Poultry), so peace reigns again in the Lyle household!