My feeling was right the caliper from bolt to pad measures 55mm. I need 65mm. Compared a 700c and my existing tores brake track is exactly 10mm further inward compared to the 700c. Thus by visual comparison a 700c wheel would in fac solve the problem. Sadly all I can find abandoned around here are old mtbs and a 26 inch wheel
is useless. May have to get a new one or try and find an almost dead donor bike.