ok... forget about the old heat shield fixing points... they will have rusted and seized screws that will round and break off when one tries to free them.
get some new penny washers and new screws.. of your choice..
break away the heat shield around the rusty seized fixings.. free it and take it off.. you can use exhaust paste and thick aluminium foil, or plumbers heat mesh pads ( from B and Q http://www.diy.com/departments/bq-so.../161521_BQ.prd
) _ which will stick to it.. to repair the heat shield where its damaged, and reinforce those holes and patches with heat mesh, as you need to... the whole repaired heat shield can be sprayed in silver exhaust paint..
when you have freed off the exhaust mounts and done repairs.. replacements etc.. you can put the whole lot back together..
using the new penny washers and screws you have bought.. and drill in new pilot holes, close to the old fixing points or where you want to.
i told you in my first post .. you have to be inventive.
not least.. you could make a new heat shield from scratch using Mocol heat shield cloth and Zircotec from example http://www.demon-tweeks.co.uk/motors...ing-protection