Right, day off today so had another go at sorting these brakes out.
Jacked the rear of the car up and supported on axle stands.
Gave to bias valve a spray/knock and set it open.
Used my new pressure bleeding kit and did the 2 rear calipers - got a few bubbles from each side, pushed the bias valve in/out a couple of times, bled again and got a few more bubbles.
Then jacked the front end up and bled the front 2 calipers - got lots of bubbles from n/s/f and a few from o/s/f.
Removed bleeding kit, started engine + brakes have alot more feel now!
My only question is, where is the fill line on the brake fluid resevoir as can't see any 'max'/'min' markings on it?