what about euonymus japonica you can get green and white and green and yellow varieties and both are evergreen. quite quick growing and our neighbour has them in full sun. though mine are in shade.

I've always liked English Yew. Had one for 30 years, never an issue with it. Looks especially nice in winter when everything else is brown/grey/blah & those red berries are very ornamental.

Another fave is Wintergreen Boxwood. Does exactly what the name implies - deep emerald green leaves all winter. This seems to meet your specifications. Here is my friend Jim's video on Wintergreen Boxwood.

https://www.youtube.com/watch?v=p2n0SvYDLFY

Hawthorn is a massive winner in wildlife terms.
Sounds like you've spent a lot? Maybe carry some secateurs & plastic bags to take cuttings from things you like that are thriving locally?

I planted a hedge of Escallonia Iveyi but it was constantly going yellow and it became straggly and lost foliage at the bottom also held on the he dead flowers. I dug the whole thing up and replanted with yew (Taxus) and it was the best decision I have ever made. Easily shaped and disease-free; makes a wonderful formal hedge.

There's a list in the link below of plants commonly used to make up a mixed informal hedge

https://www.ashridgetrees.co.uk/gardening-advice/how-to-plant-hedge/hedge-plants-informal-hedging

All these don't mind being cut back. The trouble is, I don't think anything's going to grow as fast as the Prunus Green Torch you've already got - but because you're going to cut it back every other year, it probably doesn't matter much - over time, it will all blend in together. I note you mention Viburnum - there are a lot of varieties of Viburnum, so I'd stick to the V. lantana mentioned in the link if you decide to use any of them.

Its probably just as well the Skimmias gave up - they wouldn't have been too happy being cut back biennially, and most only make around 3 feet in height anyway.

Good choice Jim. The Yew can withstand any amount of pruning and forms a dense evergreen hedge with red berries.

Whilst the idea of a mixed hedge might be a wonderful thought for wildlife; they do grow at different rates and can become rather untidy in at town or semi-rural garden. Also they many items will be deciduous and the fact that they grow at different rates and might need to be pruned regularly will mean that you will lose the flowering aspect. I regularly visit stables where the owner planted a mixed hedge with Viburnum, Prunus Spinosa, Hawthorn, Holly, Beech etc. but as it runs along one of the paddocks it doesn't look out of place and hasn't been pruned up to now.

yew [Taxus baccata the European yew] is quite slow growing and if you want berries you will need to have male and female plants, but it takes to pruning really well.
But all parts of it is poisonous to humans and livestock so that may be something to consider.

Hawthorn isn't evergreen. The trouble with quick growing is that it doesn't understand "stop at n feet so in a mixed hedge you want to be neat you'd be wanting to trim parts of it and not others, which is something to consider. You mention Eleagnus. Its a great reliable shrub but there are several varieties so do compare different ones on line.
I have "Limelight" grown as a stand alone so not clipped, just trimmed back as needed after flowering. The flowers are insignificant and easily missed but smell wonderful. I hold back clipping it back until the flowers have finished but bring a few into the house to perfume the room. As a clipped hedge you might want to go for a little wider than 3 feet though, if you want the flowers. E. pugens maculata is an attractive variegated one.

I have 1 single yew tree, don't know if it's male or female, but it produces many red berries every year. It must be wind pollinated. If you plant a hedge, berries won't be an issue. You'll get them, the birds will eat them. I need to prune it every 2 years. The growth rate is reasonable - about 6 inches per year. I find it very low maintenance. It won't bother you with pruning every other week and is amenable to formal shaping if you like those fancy cuts. Makes a good wind/privacy screen. Will stand up to the worst storms - blizzards, tornadoes, hurricanes. Mine has.

If you get berries then it is a female Paul and yes the English yew [Taxus baccata] is wind pollinated. I need to have a go at pruning back a specimen that is part of a mixed hedge.

You're absolutely right SBG - duh for me. I would never doubt you.

Many thanks to everyone for the suggestions. We've been going through them, debating which might be right for us. Much depends, of course, on availability, but I think we now have enough information to make better choices than before. Time will tell!