This may be the next panel I attempt to repair, has anyone got any ideas of where to start, anyone repaired one this bad in the past?
Thinking about cutting off what's left and starting again?
Have a friend who says I could "bond" and new panel on, has anyone tried that?

Your thoughts please chaps before I dive in...

Yeah just chop it out and start welding. You might not replicate the exact curves as the original but it should be possible to fabricate something very similar. If an exact copy is what you require then you could look to getting an original part from a donor vehicle.