Brake Problems: Transit Tourneo 2011 MK7

I am having a serious headache with the brakes on my 2011 MK7 Transit Tourneo, about a month after buying it the brake pedal hit the floor whilst driving, after inspection the bleed nipple on the passenger front caliper was loose, the bleed nipple was tightened and took the bus to a local garage (very slowly) and explained the problem, they had it for over a week and and deduced that the master cylinder was at fault and fitted a new one, pedal was now good and all was fine until after about 15 miles of constant driving and the bus came to a halt, the brakes were now stuck on, left it to cool down and they freed up so back to the garage and explained the new problem, he had it for a couple of hours, phoned up and said theres nothing wrong with the brakes, went to pick it up and explained the problem again for him to say the only other thing it could be is the caliper, see how it goes and if it does it again ill put new calipers on it, off i went and not even 10 miles down the road stuck on again, let it cool down and managed to limp home, i have done some spannering in the past mainly older cars so decided to have a look myself, its had new discs and pads on the front (before i bought it) the pistons are free, the caliper sliders are free, with the bleed nipple being loose i assume that there is air in the system so have tried to bleed the brakes in the normal way, press brake, loosen nipple, tighten nipple, let go of brake, but all i have manage to acheive is the pedal now hits the floor again and hardly any fluid comes out, i did some research and found that because the bus has ABS and traction control apparently i have to perform an ABS bleed, so i have downloded FORscan and bought one of the more expensive OBD11 leads with HS and MS, hooked it up today and alas no ABS bleed option, i have even upgraded to the extended licence, so i am now stuck with the bus on axle stands and a brake pedal that hits the floor, sorry for the essay, any help, advice or guidance would be much appreciated.

Thanks

Dave