Laburnum remedial problem

I have a well established laburnum tree - with something like a 4-5 inches diameter trunk - which is now resting at a 45 degree angle having been clonked on the head by a much bigger tree which was felled some months back.

It's probably not going to be practical to right the laburnum. So; question: If I chop the labernum doing to the ground, is it likely to regrow (i.e. can it be coppiced) or is it more likely to die? And if it can be coppiced, is there a better or worse time to reduce its size?

thanks