Do it from below.
Remove the steel X support from underneath, 4 bolts.
Use an extension to take off the passenger side spring bolt, then swing the downpipe to that side.
You will need 1-2 extensions with a swivel to get to the driver's side bolt. Wrap electrical tape over the swivvel to prevent it from bending too much.

 

Got them cracked - accessed from under the car on jack stands.

For anyone's reference in future I used a 3/8 flex head ratchet with a 300mm extension, 3/8 swivel socket and a 14mm socket and a couple of sprays of this WD40 penetrant over the last couple of days (don't spray it on when the engine is hot though)



I didn't have to remove the x-brace as yet, but will do this when it comes time to remove the downpipe. (doing this now so don't have to fight for hours when it comes to getting the new exhaust installed.)
x-brace looks to secured by 13mm bolts...