Early this year [2023] this little pyracantha leafed out and then they just died off and I thought that I had lost it.

So it got dumped at the top of the garden, naked………… not one leaf on it and forgotten about. As we approach winter I noticed this new lease of life in October. Might have lost a few branches but it is at least alive. Now the surface soil and pot has been cleaned up and tree will go into an unheated greenhouse for the winter to protect it and keep it going until next year, when it will build up strength. Moral of the story with everyone losing trees, give it a chance and see what happens.