Which version of the flow meter? - the one with a 5 V d.c. supply (because that can be common to the flow meter and the emonTx/TH) and with the pull-down pulse output.
I don’t know pipe size, if temperature is required, etc, so I can’t be specific.
I think it’s VVX9CS N B 0000 2 XXX
I don’t know what the last 3 characters should be - 52P | 527 | 528 - that depends on the pipe fittings.
(The copper I usually deal with doesn’t have a hole down the middle )
Studying the data sheet more closely, it appears you get an analogue output as well. Which questions the label in the photo: Pin 4 (per the manual) is the pulse output and never anything else according to the diagrams, the label says 1 pulse per 1 litre (I think - but whatever, it does give a value) yet the label also says “do not connect” to pin 4.
I’d be inclined to put a multimeter on volts from Pin 4 (+ve) to Pin 3, a 5.6 kΩ resistor (or bigger) Pin 1 to Pin 4, and see if there are pulses there.