Stu, C pillar repair isn't too bad. You'll need to have a good prod and poke around though, they often rust out at the bottom so you'll likely need to cut the bottom off and fabricate a new section but make sure you check the condition of the reinforcing inside the post as it is stiffened internally with thicker steel. Apart from that it is a case of welding the bottom of the post back on to the inner and outer wheel arches. HTH