Stripped cylinder head bolt?!?!

YEY !! Brilliant news mate   Glad you got there in the end, and you made a new friend! cant be bad

Thinking of using these to repair this crack from the thread to the water jacket. Any thoughts?

Pesky EG blocks. This is the third block I've got and theyve all been cracked across the head threads.
It may never leak but I don't want to risk it. its either a thread insert or try and get it welded or stitched. Going to speak tomorrow with a company that repairs this sort of issue.