I get the marshmallows from Sainsbury's. They are 68 pence a bag - 2 points for the whole bag. Lovely floating on an options hot chocolate or put on top of stewed apples/rhubarb and grilled til soft and gooey.
My local Sainsbo's is only a small one too, but I asked at Customer Services if they would get them in. I told them that if they were to stock them I would inform my class leader who could tell class. If we find any 'new finds' we bring in the wrappers/cans/packets for others to see and get ideas. Sainsbo's got them in for me!!
I took an empty pack into class and I know the class members have been buying them too so it's worth a try. If you don't ask you don't get x