Disco 2 Best way to drain a small amount of coolant from a TD5

In short, I had a problem with an air lock whils on my travels. I sorted this out (whilst learning a very valuble lesson in not ever buying cheap coolant tank caps again!).
Anyway, the long and short of it is that my coolant has become quite diluted and I need to add two or three litres of OAT.
What would be the easiest way of draining this off? Direct from the resovoir i.e. just disconnect the pipe and drain off or is there a recommended way?

Hi DosBox,
How old is the coolant? It may be just as easy to drain and refill with fresh. Not difficult to do. Drain from hole in bottom of steel pipe. When you re-fill,unclip & raise expansion tank, open bleed screw and fill slowly till no more air comes out of bleed screw. DO NOT overtighten bleed screw as it'll snap!
HTH,
Griff

The problem was with the last refill (had a new cylinder head!) I suspect.
The coolant is brand new (a month old) and I really would like to do this with the minimum of fuss on my drive.