Talk about a silver bullet, spot on Aidan. Thank you.

Actually reminded me I have seen exactly the same on a Terrano, but it was several years ago.
The filter is a deep in the pump held down with spring. both can be fished out with a bent wire hook through banjo hole. Filter had substatial amount of sludge like material, blew it clean with airline.

Engine now pulls well from 2250 onwards, this must be speed that fuel flow rises fastest.

Now on to the dragging brakes and slow puncture....