On Mon, 13 May 2013 20:48:30 +0000 (UTC), Jules Richardson wrote:

a) What's a good type of gravel to use? ISTR local concrete firm
suggesting pea gravel

I'd have thought you want something that will lock together and compact
to a firm base, like MOT1 this side of the pond. Crushed stone straight
from the crusher, so 20 or 40mm down to dust, compacted with a
vibraplate.

Yep:

http://www.pavingexpert.com/subbase.htm

Really for a drive than patio but you still need a good base.

--
Cheers
Dave.