BW66 cooler options

Just use the five position selector, and adjust it so that you just lose position "1", you will still have first in "D", and if it's a Jag box you'll still have it in "2" as well.
Cheers - It was sold to me as an SD1 box, and the pan is no deeper than the BW65 I have in the shed so I'm guessing it's NOT the Jag one.
If it's a Rover box then position "2" will be SECOND gear only, but you'll still have FIRST in "D", so perfectly useable with the five position selector.