Oooops forgot to do a 50/50 test straight away and I'm not there now. Its been bubbling since 2ish is it worth getting the folks to take a sample now?
Well..
I drained some more off before starting as its had had 48 hours to settle, I ended up taking about 5l off leaving 145l to start. I'm pretty sure that oil I drained off is quite dry (hot pan test) so I'll drain a lot less next time.
I then did the calcs you gave me (based of 150l rather than 145, just realised

). Anyway that meant 15l meth 750g NaOH.
The reaction was complete in under 10 mins
Drained 20L of glyc
The 45/5 test then resulted in 1.25ml of veg oil so 75% conversion so far.
Based on what you gave me, I then added 3.35l of Meth and 167g of NaOH,
I mixed for another 10 mins
Drained about 3L of glyc
The 45/5 then gave 0.45ml of veg oil unreacted meaning 91% conversion.
I must have made a mistake somewhere though as I started with 145L, added a total of 18L of meth, and drained about 23L of glyc, yet ended up with 134L of bio before draining the tank. I'll pay more attention next time.