Tree fungus?

We have some weird growth on one of the branches of a cherry blossom tree. The tree is not in good health but we are desperately hanging on to it as we get a woodpecker visiting in it. Can anyone identify the growth please?
Wondering if we should cut off the affected branch to prevent it spreading elsewhere or whether it’s ok left as it is.
The growths are mostly hard - the last picture is one of the bits broken open.

Many thanks

 

It obviously a fungus, I'd not like to try to name it, but I dont think your tree has much longer to live.
If it is just one branch you could try cutting it off but you would need to cut back a couple of ft at least passed any signs of the fungus.

Wood peckers like old trees that are on their way out, its probably riddled with beetle larvae, which they like to eat.

 

Thanks Pete, gutted on several levels! Not 2ft clearance below without taking the biggest branch, and we lost another in Eunice so maybe time to let her go