First I have to drop the old oil. But the male square drain plug is nicely obstructed by the brake cross-shaft and the drawbar bracket.
I've measured the drain plug and it appears to be a square of side 9/16" (14.25mm) . So I need a square female socket of that size to get it off - which seems to be a hard socket to find

How do you get your plug out - is there a crafty way.....?
TIA