What is EHH and 18BKt?

by David O'Connor
(Edinburgh)

I have a ring with EHH and 18BKt on the inside of the ring. The B is smaller than the K even though they are both capitals. It is white gold. However it came up as platinum on the receipt?

What does EHH stand for?
What is BKt?

Any other relevant info would be great, thanks.
Hope to hear from you soon.