Mystery Mullard ECC83

[chrisaxe]

Hello,

So I picked up an old Mullard ECC83 from a market last week, and was wondering if anyone could help me out with some more information about it. 

A lot of the print had come off, but you can make out the Mullard shield logo, and the ECC83 labelling. There also is a three digit code printed towards the bottom of the valve, B7H. 

My limited googling has uncovered that Mullard used three digit codes up until the early 60’s, so could be ‘57?

Any information would be greatly appreciated - particularly the age of the valve, and possibly its value if I were to sell it. I really don’t know too much about it at all.

I’ve tested it out in my amp and it works fine. 

Thanks,

Chris.