In message , John
Rumm writes
On 06/07/2018 22:23, Tim Lamb wrote:

OK so I have finally reached the coupling up the basin taps stage.
Sadly the advance purchase of 15mm cu to 1/2" tap are all* female
fittings where the poxy flexible tails need male couplers. I think
Toolstation do something suitable but delivery only.

I usually use a 15mm compression / compression service valve... take
the nut and olive off the tap end, and screw the flexi tail nut
straight onto the valve. The tap nut should include a rubber seal in
the nut.

Yes. They do.

Also do tapered thread fittings exist anymore?

They do. Sometimes required for gas work, but seldom for water.

I have a set of bath taps with a single spout outlet. The
connections appear to be parallel thread female 1/2".

Unusual for a bath tap IME.

Inadequate description. This is a wall mounted bronze? casting for
filling over the bath side.

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:-)

--
Tim Lamb