I just couldn't see where on earth I was supposed to connect to under the exhaust manifold.
So, luckily Chop took the whole old engine to me and I nabbed the adapter and fit the drain onto the block, as per my Block picture above.

It was because I didn't want oil dropping back under the rear tyres......!!

Is it supposed to fit to some sort of adapter that fits on the sump drain plug? That seems to be the only sensible place to put it, as it's under the oil level and the sump can be drained through the adapter instead of taking off the swirl pot connection also.