well what i did in the end was get a full stainless steel catback exhaust, dont bother the silicone tape it failed prett quick, get the flexi off ebay, the best option for repair, would be to get the correct flexi, (the sizes are in my thread) cut the old one out and get your mate to help you weld it in place. (im assuming if he repairs mini's he has a welder)
if he dont then an exhasut place will fit the new flexi for cheap.