Welcome, Goodwood!
To help you, we need a few particulars:
Is it growing in the ground, or in a pot?
Did it dry up suddenly, all over? Or was it a more gradual process? If the latter, how did it proceed--i.e., from all the tips, or branch by branch, etc.?

any webbing present on the plant - you need to inspect closely? How long have you had it, as well as whether its in the ground or a pot...? Assuming you've had it a few years and its in the ground, I'll take a stab in the dark (not enough information really) and suggest Cotoneaster Webber Moth, info in the link below

https://www.rhs.org.uk/advice/profile?PID=647

there has been a bacterial disease that has the effect of the leaves and berries shrivelling. cant remember what it is called though. looks a bit like fireblight.

Cotoneaster is subject to both fireblight and bacterial canker. Both of those start as dead twigs and/or branches before killing the entire plant. Was it showing those symptoms for a while, Goodwood.