3/8" push fit

hi folks..enjoyable threads!

I had a chap in to fit a doulton under-sink water filter with a John Guest 3/8" push fit inlet & outlet. He used 10mm plastic tube instead of 3/8"
one side was okay but the other leaks.
he can't get the leaky pipe out.

Any solutions instead of buying a new head for the filter.

I suggested drilling the pipe out of the connector with a slightly larger drill to make way for araldite-ing a length of 10 mil tube into it which would also form the seal.

anyone recommend this as the simplest cheapest solution or have another idea?

or maybe a different adhesive?

thanks!