MX5 Normal corrosion at the rear of the outer sills, local body shop cut out old sill weld in new metal and spray ,last time I checked was around £500.00 they could probably include front floor section. New brake caliper on the rear, dont forget parking brake adjustment is on the caliper 5.00mm allen key in behind a nut.Front brake binding, how bad ? normally DVLA recommend failing at 50 on the brake meters. Exhaust I take it is dragging on the ground ? if not its still supported from some other mounts so not a fail.Bulbs and tyres normal. End of the day you could be around £7-£800 if u need to replace front calipers, chances are it would only be the pads or caliper pins seized
Good luck..