Brilliant options and thanks guys.
I think so far the practical side of me is thinking, just get a set of used STI seats that I know suit my small frame, get it reupholstered to match the interior and add heated elements to retain the heated seat functions. Very easy to source, should fit without messing about with rails etc, reupholster shouldn't cost a huge amount for 2 seats and I don't have issues with fitment going forward. Also, I could sell my current seats if anyone was interested in them as no point keeping them.