Can't help you, but if you decide to upgrade the old washing up bowl to one of those waste oil cans with the draining board on the side, be aware that when you remove the sump plug, warm oil will slop out faster than it drains away and run all over the floor. I found this out the hard way yesterday, it was OK though as the car was parked on the road outside a neighbours house and not mine 😉
What may be helpful, is I just bought a strip of socket style hex keys that cover a range of sizes up to 12mm. 12mm fits the sump plug on my huge van and tiny Punto so sounds common.
