I took off what looked like a radiator bottom hose (small hose bottom left when you take the grille off) plus the bleed screws, reservoir cap, and waited for it to drain.
After a while the water stopped coming out so l refilled it, but it only took 6.5 litres.
Where was the other 4+ litres? Did l miss something? Fortunately the coolant that came out was not discoloured and tested fine, so at least it's got 6.5 litres of new antifreeze mix in it now, which is better than nothing.
And l used the pink OAT stuff which looked the same as what came out.
It was last changed in 2011.
You did not remove the bottom hose it was the fuel cooler coolant pipe by the sound of it.
The fuel coolant pipe removed will drain the coolant from the radiator as it attaches towards the bottom of the radiator but it is not able to drain all coolant from the engine block. This is where your missing coolant is located, still in the engine block.
The bottom hose is accessed from the engine side of the radiator not the grille side.
Open the bonnet and remove the plastic radiator cowling cover, (4 locking screws 1/2 to 3/4 turn on each will free them).
Whilst you are standing at the front looking into the engine bay, look towards the right-hand side of the radiator about 3/4s of the way down you will see the thermostat housing it will have three pipes attached to it follow the lowest pipe to the radiator and that is the bottom hose. Removing this from the radiator will get most of your coolant out (will still be some in the system but very little).
Just a note the top hose should have a bleed valve fitted (not all after market pipes have them).
When re-filling with coolant this valve should be unscrewed to assist in getting the air out of the cooling system, remember to re-tighten when coolant starts to come out of this valve indicating air removed.
Run the engine for a while with the header tank cap off this also aids the removal of air from the system then replace cap.
Check after a run to see if coolant level has dropped indicating more air has bled from the system top up should now be fine.