Maybe if you live in Alltnaharra holly is about the limit of what you can grow as an evergreen bush (though I bet the heather grows high enough to be hedge there). But in most inhabited locations, even in frost pockets in Shropshire, you'd get away with quite a lot more. It has to get pretty cold to kill cherry laurel. I believe it succeeded in doing that in parts of Germany recently, but it was -28 or something. Not seen much evidence of privet hedges being killed by recent winters. Nor viburnum tinus. Though these are fairly boring things.

There are various evergreen Berberis that I have seen no evidence of dying despite recent winters, and seem to be excellent hedging.

Box (buxus) is a native, growing high on hills in the Chilterns, so must be pretty hardy - though it can apparently be killed by some nasty disease going around called box blight. Christmas box (sarcococca) makes a nice hedge, or insert into one, and seems hardy enough. Some Osmanthus spp seem fine too. I could go on.

On the other hand, my bay was frozen to the ground last winter by a mere single night at -10, having survived the previous two winters. Griselinia has survived fine around where I live, but I have heard of it being killed a few places.