T350 - Removing rear underside exhaust cover

[TvrT350t]

This is the second time my hanging brackets have stretched on the rear silencer now within 2 years and have made the exhaust drop down!!

This time i am finding it impossible to undo the two middle nuts & bolts - any ideas anyone? Im using two size 10 spanners and wd40 but am having no joy at all!! The alan key bolts are easy to remove apart from the two middle bolts on the underside of the vehicle!!

I've also read somewhere that you shold but cable ties around the hanging brackets to hold the rubber once it splits to prevent this happening again - worth a go i think

Please help