From what I see, the field should always be hidden. Any value that you choose for Field1 will result in a "True" result and thus, a hidden field. If you select "value 2", then the first part of the expression is true, the field does not equal value 1. If you select value 1, then the second part is True as the field does not equal value 2. If you select any other value, both parts of the expression are True.
I would use:
Field 1 ≠ "value 1" AND Field 1 ≠ "Value 2"
Thank you so much for the advice; works just fine. Can't believe I was so thick as to not see this solution. Anyway really appreciate your help.
You have a lot of company. I've seen quite a few similar posts here.
It all stems from the "not" in the not equals when combined with the Or between your terms. That Not "flips" the needed operator from Or to And.
The easiest way to debug such issues is to pick different values for "Field 1" and then evaluate the expression by hand, being careful to respect order of operations rules.