Sheridan was a loose head... 6'4 I believe
I think Ben Harris us also a 6'4 loose head
Someone like Phil Vickery was a pretty tall tight head... 6'3 from memory
I believe JTA is 6'3 or 6'4
It's quite common for props to be a couple of inches over 6 feet these days.
Besides, before lockdown, he was showing glimpses of strong scrummaging, but often followed by a penalty or getting himself slightly in the wrong position.
I suspect, like with a lot of SH imports, he needed to adapt to the NH game.
It's quite possible that scrummaging has different nuances in England than it does in NZ