I've never understood why the companion care advice is different...and in fact I think some of it is completely duff and indeed a bit dangerous! Annoyingly (or actually probably a good thing seeings its so rubbish) there doesn't seem to be a direct link to it, but their rabbit care neutering advice says that male rabbits do not normally need to be neutered and that the ideal (yes, it does say ideal) combination is a spayed doe and an entire buck...
I raised this one with the RWA a few years ago, especially as it's written by John Chitty, and was told they would raise it, but it's still there and still says it!
http://www.companioncare.co.uk/pet-health-information.html (click rabbits, then click neutering).
Small mercies that the information is so hard to find that hopefully no-one will bother.