Homo Extreme Dilute Black would be my guess though it is claimed the gene is not in the UK.
Here's a few pics of adult and juvenile Homzygous ED Black
Amal 11-6-14-a.JPG
same hamster at 7 weeks old with his normal Black Band LH brother
Amal and Felix 9-4-14.jpg
Here are some random pics of 25 day old pups from my Extreme Dilute Black litter in Satin and normal coat.
H13 Litter day 25-b- Homo ED Black male.JPG
Note the red glow to this males eyes in this photo
H13 Litter day 25-e- Satin Homo ED Black male.JPG
H13 Litter day 25-l- Homo ED Black female #1.JPG
Your friends pup has dark ears which is not correct ear color for a Chocolate. Some hobbyist I know like to wrongly call Homozygous Extreme Dilute Black the false Chocolate.