Ok, it's mega stuck, rounded off and I want to cry.

Can anyone help me with some extra ideas on how to get this bolt out.

It's the number 4 bolt holding the injector in the block on my 1.8 TD transit connect.

I have replaced all 3 of the injectors but this one is faulty and it's the only one I really needed to change!! ha ha.

Ok, I tried

Day 1

almost a full can of WD40, 6 + hours of soak.
Heat to the point of cherry red and pipe freeze in cycles.

the 10mm head rounded :-(

Day 2

I bought the Irwin remover kit............total bobbins, won't grab it enough to turn with any force and further chewed the bolt head.

It's just under 10mm spanner width now, but I can't wedge a screw driver head in to compensate due to not being able to swing the spanner in any way to losen the bolt due to space.

It won't take a 9mm socket, 10mm socket slips, I can't get grips into it as it's slightly sunken and I couldn't get any force on it anyway if I could.

Properly peaved off!!!!

HELP!! ha ha.