All done.
Sump bolts were actually different, original was a 17mm head, 14mm thread and about 20mm in length. New one was a 19mm head, same thread and about 40mm in length.
Copper washer on old one had had it. New one is in with PTFE tape on the threads and tight. As it's almost twice the length too I imagine it's got a better ability to seal.
Edit: A strange thing happened too, the old oil turned my gloves and skin bright yellow.
Edit 2: Apparently water in the oil can cause it to be yellow, this is the same oil that was in there when I changed my PCV valve so maybe it will stop now.
Also, as I'm a delivery driver, it's a lot of short trips. Anything I can do to minimise it?