I think you asked about this before Avril, and yes its worse now - doesn't look as though anyone on here has any suggestions. Is there an organisation in your country like the Royal Horticultural society for example who might be able to do some testing for you? As privet grows quite quickly I'd be tempted to dig one of the bushes out and see what's happened to the roots.

honey fungus does this to privet. it happened in our garden. the RHS advice was to pull up the dead ones and the live ones for 1m either side of the gap. I did this and the rest are fine. I then planted the gap with other resistant hedging plants. so I now have a mixed hedge.

Have you banked up the soil around their roots. apparently this is what caused mine to fall 'ill'. then the Honey fungus just helped it along. have you noticed any toadstools at the base?
take some dead stuff and peel the bark off does it smell mushroomy? has it a white tissue/fuzzy /felty layer under the bark? if yes to either then it does have HF.

Thanks so very much for your replies S and S.

When the rain ceases, I'll have a look at the base for these toadstools. I've just realised that the dying part of the hedge is just behind an old tree stump (impossible to remove) which in autumn has toadstools growing from the roots. If this is the reason, and if I replaced the hedge would the same thing would happen?

Not if you replant with a variety that isn't affected. You might not see toadstools at this time of year unless there rare remains of some of last years,as you've seen them on the stump it sounds as if that's the trouble - they can spread under the ground over a wide area..

I used blackthorn and hawthorn in my replaced section. The rhs website lists resistant species. Don't plant privet again though.

Thank you very much indeed again.

SBG do you find the blackthorn suckers? It pops up every where here and is quite difficult to cope with. Flowers are a delight in spring though so it all gets forgiven every year.

I haven't noticed but to be fair that bit of the garden needs a total revamp.