Not tried Westway but I use Mannol Safari 20/50 for engine gearbox and primary. I've also tried 10/40 semi-synth in the engine which also worked fine (little noisier perhaps). This time, I experimented with a 50/50 mix of hypoid 80/90 and 20/50 in the gearbox/primary to see if I could eliminate some oil leaks. All works fine except the oil still leaks. On the whole, if you change every 1000m or so (engine), pretty much any decent 20/50 mineral will do.
