Thank you for the further information. I will definitely rewrite my code so it is clearer what the code is actually doing. You are quite right, for years, I have always assumed that the code was doing something completely different to what it actually was doing! Which is why it didn't work with the original = 0 options because it was still returning true! Now it makes sense!

Very interesting. I will book in some time to update the code to reflect this and to just tidy up the general coding as well as the scripts have evolved over the years and need a bit of trimming. Thank you.