Plums

Probably not.  They may have cross pollinated with a different variety, and unless you graft them onto a suitable rootstock they could take many years and get very large before they even thought about cropping.

Were they English plums?  If they came from Turkey or wherever the variety may not be suitable for the English climate.

Gillie

You can grow a plum from a stone that is how they have managed to get the varieties we have. Take plum A with characteristic that is wanted and take Plum B with another characteristic that is wanted and cross pollinate lots of the flowers. Then plant and see what comes out of the pairing. The two characteristics that are wanted may appear in one of the pairings

The problem is that you have no idea what the plums were nor what the pollination partners were. You may get a good one or a bad one.