Thank you @Antonio Garcia Martinez for raising this, as I've just learnt something important and @Marc Mundt for pointing me at the right place!
 

Thank you @Peter Steiwer" href="https://javascript:" title="Copy to clipboard">@Peter Steiwer that nailed it swizzling .found. 

Thanks for the advice @Vitaly Furman, I used  square bracket syntax as I was iterating over an array.

I did try my code using {} brackets and my code still isn't ending the nested IF loops upon finding the field and value that match.

Regards

Stuart