Dear Kemi,
I found it, and it is not what either of us thought. The sheet in our cabinet is not the 1974 Glen Affric collection at all. It is a duplicate that came to Bergen in 1988 as part of the Ferreira exchange, and it was never properly accessioned — it has a Bergen number written in pencil on the reverse and nothing else.
The determination label is in Ferreira's hand, which explains the 1988 date you could not account for. He must have determined both sheets at the same time and sent one on.
I am photographing it this week and will send images rather than the sheet itself, unless you would rather have it back, in which case it is plainly yours and I will arrange the courier.
With warm regards,
Hanne
P.S.The pencil number is BG.11402, if that is useful for your side of the reconciliation.