Re: To all of you with older phones...
"While I agree with your sentiment I must point out that some custom ROMs, like CyanogenMod, actually don't execute as rooted by default."
Lucky you. I installed CM11 (or maybe 12) on my Galaxy S3 when Samsung stopped issuing updates.
There seemed nothing that I could do to make the Barclays mobile app to not claim my phone was rooted. I know that there were a few settings to try and prevent the detection of the 'root', but none of it did the trick.