One step forward - two steps back............. My decision to not bleed the brakes turned out to be a good one. As I progressed the ARB installation it be came clear that the re-routing of the rigid brake lines wasn't enough so both sides had to be disconnected and re-routed, at least with the ARB in place I could see exactly where they needed to be.
When fitting the down link it was very close to the upper wishbone and looking at the build manual the design had the headlight mounting bracket which would get greater clearance. I stripped down the bell cranks and the front upper wishbone mounts and packed them out with two extra washers and this gave additional clearance. Next was a re-bleed of the brakes with James' help.
With the wheels refitted and the car ballasted with 85 kgs in the drivers seat I adjusted the downlinks to a neutral position with the bell cranks horizontal. Then a run around all the nuts and bolts torqueing them up and tie-wrapping everything back in place followed by finally refilling the cooling system.
I couldn't resist a final gratuitous photo of the calliper and disc.