The message
from Paul Barker contains these words:

15mm compression fittings all have 1/2" male threads on so these can be
used without the nut and olive for certain jobs.

The same is not true for 22mm, these do not have a 3/4" thread. What a
missed oportunity?

They did once. I thought they changed decades ago but at Xmas I had to
replace an inline valve that had been bought only about 3 years
previously and found that to be 3/4" bsp while the replacement had the
finer thread.

--
Roger