That looks pretty dead to me Christine
Mine gets like this every winter as some branches get frozen to death, especially at the tips. I take out the grey ones in early spring, cutting back to red stems then give it a good top dressing of pelleted manure and a liquid tonic of tomato food and then I wait.
By the end of May it's clear which stems are live and shooting and then I cut out the rest. Sometimes late spring frosts do a bit more damage. My tree is now about 8 years old and 2.5 metres high.
Thank you both for your advice. I will get dense of the dead stems and then see what happens.
It may be a blessing in disguise as the tree was far too near the fence and would have had to be removed quite soon anyway.