I've been out on the bike for several hours today for the first time since I adjusted my suspension. It's massively improved, it's like a totally different bike.
After much reading of this thread and others on the subject I've gone for 6 on the rear shock and one turn out on the screw. The front forks are showing 3 rings and one turn out on the screw.
It's not perfect by any means but a dam sight better than it was before. The bike is now very stiff, probably a little over stiff to be honest. An uneven road surface on a country lane can shake your fillings out so may need to back it off a bit but not much.