Job's done! A couple of tips:
1. Pop the rear boot before you start just in case you need something from there before you finish
2. There was a circa 8 second delay from when I disconnected the top fuel lines to when they began spewing forth raw fuel - so be prepared with a towel to soak that up
3. Don't forget to put the new tank gasket in BEFORE you connect the hoses and wiring harness (doh!)
Here's what the cracks looked like: