After a re-measure today of the rears, it will maybe just fit.
I had a 17inch rim handy with no tyre;
Measuring along the top of the 17's I need 2mm more clearance to the flexible part of the break line..
once I go to 18 it should be 0-1mm clearance, So how hard is it to bend the break line while still on the car.
everything else clears by 10mm at 17inch and clearance will increase the larger the wheel..