Yes i had it fixed first up with a hose clip but it slipped and changed the timing lucky it was on the ground.
Its in a area full of heat and vibration and in the air that would have been a dead stick.
Its best to re-drill but good luck if you don,t.
If you find the problem let us know as we all learn from these problems.
Its always good to have a complete ignition set up as spare so you can swap and see and eliminate problems, the rexel's are so cheap and good its not worth the frustrations of not having a spare, but dump any Chinese spark plugs quick smart.
Dave.