Philadelphus wouldn't be my shrub of choice to make a hedge. If it is a sheltered position in a non-hostile climate then Myrtle, Luma apiculata would be my choice. I know that the leaves of Osmanthus × burkwoodii are quite similar to the privet that you want to replace but the scented flowers and evergreen leaves would do fine. Or how about the hawthorn Crataegus monogyna, loads of scented flowers, haws in the autumn for late season interest and food for the birds.

Go for Belle Etoile - its compact and highly scented with double flowers, whereas Beauclerk has more arching growth, also scented. Sadly, double flowers will mean they're useless to the bees though... I take it you're replacing your privet with an informal mixed hedge? And obviously, Philadelphus is deciduous, if that matters...

And say no to Hawthorn or Holly or any other shrub with thorns or prickles. They are the devil to cut to keep in shape.
Er. P Belle Etoile has single flowers with a punk/purple base, not double.

Thank you for your suggestions everybody.
I'm not replacing the hedge as such, just getting rid of the bottom half of it and am now on the last lap. It doesn't matter about it being deciduous because there's the lower branches of a mature holly behind it. (Sounds unlikely but that's actually growing at the foot of a steep drop immediately behind) I have wanted a scented philadelphus ever since we had to leave one behind at our last house. I was thinking of putting a red Pittosporum there but it wouldn't like the wind.

Bamboo I've checked again and all the pics of Belle Etoile do show it as a single? Are you confusing it with Manteau d'Hermine? There is actually room for an arching one but on balance I think you're right - B.E. it is.

Thanks again :))

You're both right, you and Owdboggy, of course - I was in a hurry and misread the description, interpreting the rather fanciful 'doubly scented flowers' to mean double flowers, which it doesn't, of course - it just means very scented. Sorry... I'd still go for that one though, and its a bonus the flowers aren't double...

Lol Bamboo - I like the idea of double scented! I will go for that one - but now am wondering where to start a new bed so as to be able to have Manteau d'Hermine as well... to say nothing of several others Derek has told me about. And to think I thought this was going to be simple!

Nowt simple about life generally - everything seems simple when you don't know much about it, but as soon as you start to investigate, you realise how much more complicated things are, or as I usually put it, how ignorant I was before...

I often think its like the layers on a onion - take one off and find another underneath! Ordered BE today and resisted M d'H until later!

Daylily's comment seems to have got lost for some reason. Thank you anyway. It arrived today, a nice plant in a 3l pot and I planted it this afternoon, in the drizzle.
All the suppliers seem to have different estimates of size at maturity but if it gets too big I'll just carve a bit more out of the lawn. Your avatar is one of the flowers isn't it Dayliliy?

Hurray - full of flowers today! Scent not a strong as expected but may be due to the weather.
Its so nice to have one of these again.