It's so incredibly simple to do, it took me barely an hour in total, here's a rough guide of what I did.
Open the bonnet, lean down and find the drain bung on the radiator, it looks like a wing nut, my p1 didn't have that part of the engine under tray intact, if yours does it would be wise to remove it, and then remove the bung, catching the coolant in a suitable container.
Remove all of the radiator hose clips, one top, one bottom and a small one also on the top of I'm remembering right.
Remove all hoses from rad.
Disconnect the wiring for the fan.
Undo the 2 clamps on the slam panel, 12mm heads I think.
Pull the radiator out.
I then laid the old and new radiators side by side and transferred the fan and cowling over to the new unit.
That's it, just do the steps in reverse, bleeding the system with the engine running and the heaters on full heat at the end
