In message , Tim Lamb
writes
https://www.bes.co.uk/straight-coupl...-x-1-2in-6685#
product-details-tab

might make it easier...


You can get male 1/2" bps to compression adaptors that also have a
flange. That will allow an O ring to go round the thread and make a
seal against the base of the tap.

Alternatively you could use a taper fitting and PTFE if you preferred.
Or even a parallel one with lots of PTFE:-)

Yup, it will work, but never feels as solid as a taper fitting.

I see Toolstation do them, item 29242. I'll have to do a shopping run
to a plumbers merchant at some time so I'll ask there. Ta!

Curiously I had an E-Mail from TMH confirming the above. When I tried to
respond by mail it bounced!

--
Tim Lamb