Look at getting the mount that puts the calipers above the seat stay. I had problems with magura Marta at 160 & 180 mm and Louise at 160 on the standard and SS mounts. The mounts only a tenner from on-one.
There are different shapes of calliper mounts/spacers that attache the calliper to the dropouts. Some cause the callipers to foul the seat stay some fit just right. I had to try a couple until I found one that worked. Otherwise the other dropouts that put the callipers outside the frame.
I think it’s common that the BB7 won’t fit in the chainstay/seatstay areas on frames with that placement? Best thing to do is get the new drop out as mentioned above. The frame comes with cable routing for the caliper in that position.
Thanks all, picked up some Elixir 1’s from the LBS at a good price so will run them for now, although going to upgrade as running BB7 on front still, from looking in more depth today at disc’s in general, think I’m gonna go for a full set of 785’s when funds allow.