Kevin yes definitely use the stiffer red brushes,
Heres a tip I only just discovered, the end of the bristles go black with like an oily crap after a while, this stops the brushes working as effective, get a rag and pour some white spirt on and clean the black stuff off the bristles.
Also change the bags earlier, at half to 3/4 full to keep suction good, alway cut hair with sisscors to clear brushes and check for blockages.
The BS36 is a fantastic vacuum.