Oh not your plum that you liked? Has there been another visit?
It's wrong time of year really for grafting, but you have nothing to lose by trying?
The tree you have snickering, could you get one of the suckers with roots on, graft on to it and pot up in a greenhouse or porch?
When we did grafting it was in spring, grafting onto bare rooted rootstocks, then they are planted out, Ive seen a video where the rootstocks were planted and person just went down the rows sticking scions in and taping up, amazing speed.