I thought maybe a poorly marked saddleback? I'm not sure. His sister is just like him but cinnamon. Neither are greywings as their spots are full-coloured (black for him, warm brown for her). His other brothers are a light green and a cobalt SF dark spangle. Parents reportedly spangle (some dark factor, not sure what) and a light green, so I'm 90% the green male is split for blue (of course, I can't verify previous owner's statement as the birds were delivered to me). The parents have also thrown spangles (violet, cobalt).
Uncertain male on left, compared with an olive on the right. Note the wing tip differences. You can see his markings start off black then end in greyish-brown. I'm sure he's split opaline too. What mutation is this?
His sister - deep full-marked spots, her wingtips do the same.
Their brother, has normal black wing tips.
The lady I bought them from bred them herself in her garden aviary, so she probably wasn't aware what genetics were mixing (just two pretty budgies breeding), which is fine, but I'm interested in genetics so I like to know. Ideas?