Hi and welcome to GOY, Turkestan Elm: This elm is a dense, deciduous hedge with small, bright green leaves. It is resistant to most diseases, and can easily thrive in poor soil too. hope this is helpful cheers

Sounds like the next Neighbourhood Nightmare to replace Leylandii, I'm afraid. The trouble with fast-growing trees is that they're programmed to race up to 80 feet + as fast as possible - just like Leylandii. There's no way of telling the plants that they're tall enough now, thanks very much, so stop growing - as they won't. I think it would be a mistake to plant anything that's advertised as "fast-growing" unless you want a hedge that's 80 feet high.

I'd go for hawthorn or beech and accept that it will take a year or two to get big enough for you, but it will be easier to control in the long run.

Escallonia might be a possible too

I use Photinia red robin great colourful evergreen fast grower and does well in my heavy clay

Prunus lusiticana-Portugal laurel, evergreen, sun or part shade, pruple-stems with white flowers and fast growing with few problems.

Thanks very much everyone for helpful suggestions.
We've decided not to try the elm but go for something evergreen instead, probably laurel.