is there any discolouration in the stem. Cut a tip off and see if there is any in the stem. I think this is fungal but not 100%.

Cant find much on line.

The blackening of the leaves and stems sugget it might be Fireblight. I would say that for the moment, remove any dead leaves and cut off any diseased wood. Fireblight is immune to most of the fungicides but if you already have some, it wouldn't do any harm to give it a spray. If it still looks it is still diseased after a period of time, then you might have to bite the bullet and replace with something else.

Oh dear, will snip away at it and hope for the best. Thanks for your help.