Galanthophile:
Northumberland yellow snowdrops can be seen, if you can spot them, during the Howick Gardens snowdrop days, usually late Jan/earlyFeb. I think they only open weekends though. Details will no doubt be on their web site.
Maggi: John spoke to us at our NCCPG meeting yesterday, topic was wild flowers of Northumberland, and of course, amongst the dozens of orchids and so on, showed us the yellows. He said he has found them growing wild around Hexham, but I know they have loads at Howick too.
He did mention one other place, and I believe he knows where the first were found too, but as a galanthophobe, I didn't pay much attention
They look like snowdrops with the flu to me, in need of a good tonic!