Zip repair.

I repaired this zip aged ago and it has been fine but last week the slider was pulled off. This is because the last tooth is missing at the bottom allowing the slider to go through the gap. The gap is small so this is the first time that has happened.  I've sewn a lump of thread in the space so the slider cannot fall off again. Fingers crossed it works. My hubby wears the coat for walking and loves it so I am trying to keep it going as long as I can. 
The pink is cloth I repaired it with last time and it is still really good.