Just sent my Sadev sequential box out for a refresh since the box was out, while getting a clutch replaced. Good news in the box was in really good shape with a few dogs being replaced but overall the tech said to use the same oil that was in it. Unfortunately, I bought this car 5 years ago and have no idea what was in it. They said Motul 75 /140 is recommended but also said there was a very good Redline product that was blue, couldn't remember what.
I've been using Redline MTL in my Caterham 6 speed in my other car, since I assembled it 20 years ago and that works great.
But I'd like to see what the consensus is from the great and all powerful Blatchat wizards.