Yeah, typo, L2D3.
The OAP (hehe, in Britain that means old aged pensioner...talk of 'banging one out' and 'doing them at an angle' is rather humorous to me) was just me having a go. I'm not sure if there is a certain form that you have to use, but I had my legs out quite wide for balance and structural stability, left hand on my hip, and the pushing (right) hand was on the floor under my face, with the fingers pointing west (if you assume headways is north and feetways is south) so the elbow, instead of bending south east like in a standard pushup, bent north east, free of the body, with a greater range of motion.
I also started from the ground rather than at the top position, after just trying again now, I can do a couple in a row provided that I'm allowed to bottom out after every rep, My lower back is too weak to hold me up in such an asymmetric way. Need planks.
Basically, you adjust the position of your legs and arm until you find a position that affords you maximum leverage and 'feels right'.
Disclaimer: I made all this shit up on my own and it may injure you.