Karsten -
I was in Darjeeling three months ago, and I came across some packets of
Castleton being sold without the Darjeeling logo. When I enquired about
it, the shopkeeper told me the teas were genuine and never mind the
logo - he guaranteed it was the real mc-coy. The shop, being as it,
situated on the Mall [along the stables way] has some other darjeelings
on offer too - but I backed out because I couldn't find a logo.
I guess Nathmulls is the safest shop.