tailored subframes

can anybody recomend a company that make good quality tailored seat subframes that will fit a cobra clubman seat?
        also when attaching harness's to the body do you know what the requirments are for the mot? can you simply make a hole in a strong part of the floor, put the the harness bolt through and secure it with a plate and a nut underneath the car?
           any help would be much appreaciated as its nearly ready for the MOT!