It Lives!!!!!!!
Finished off tidying up the pipework, another full bleed for good measure, wheels back on, get her off the ramp and the pedal is a million times better that is was and she stops how she should.
I am not 100% sure of what the actual issue was but it was between the ABS unit (not the ABS unit itself) and the front brakes friction.
I am 99% sure it was not air nor sticking calipers but more so the hoses or over returning caliper pistons.
I suspect it was the hoses or better seals in the callipers but would urge anyone with the issue to first off replace the front flex hoses. They may look ok to the eye but thing they swell and break up over time a then bulge giving poor pedal feel.
Here is a summary of what I actually did to solve the mushy front brakes on a GTV/Spider 916 with Brembos:
1. Stripped and replaced the calliper seals and dust boots for a second time making sure it all moved freely.
2. Replaced the front flex hoses with OEM items
3. Ended up replacing the 2 front brake lines back to the ABS unit as they both sheered off. It was a nightmare of a job so if yours sheer, consider replacing and jointing only the bit that sheers off.
4. After reassemble, I made up 12mm plywood templates of the pads and fitted to the callipers instead of the pads (they are thinner and thus pull the pistons out further)
5. Replaced the rear bleed nipples (£12 from Alfa, fronts were already new)
6. Full suction/vaccum bleed of the system, twice
7. Remove the plywood pad templates and lever the calliper pistons just enough to be able to tap the pads back in*
* Do this and do not push the pistons home fully as they stick in the calliper. Also, you need the pads to back off when you release the brake pedal the smallest of amounts as they rock on the piston seals. I found this a more successful way of bleeding and setting up the callipers so there is no slop in the pedal and the calliper pistons do not over return.