In article ,
Sandman1600 wrote:

Oddly, we had the same issue around the same time last year last year
and thought we might be losing it but the browning seemed to halt and we
had a lot of new growth.

Now the browning has come back with a vengeance this year.

So I’m presuming it must be environmental rather than fungus/insects..?
If it happened last year, semi-recovered, and started again this year.

Perhaps. It could be both.

As the brown needles are never going to recover and they cover 80% of
the tree, would there be any benefit in just cutting it all back?

No. Conifers other than yews do not reshoot from old wood.


Regards,
Nick Maclaren.