I have a 2014 Freelander 2 Metropolis SD4 and my supply diesel line from the mid coupling (under drivers seat) to the fuel filter (in engine compartment) has worn through by touching the engine pulley.

I’m struggling to find the correct part number for a replacement pipe. Does anyone know what the part number is and where I can buy a reasonably priced replacement in the UK?

Do you have a photo so we can take a look, i presume you could splice in a piece?

That fuel line is really expensive, over £300 when I looked, and the tank needs removing to get access to the fitting.
I'd just splice in either a coupler, or use a length of rubber fuel line and hose clips. It's not under pressure, so doesn't need anything special to stop it leaking.