thanks for the replies... think you're right... too early in the game... As I was updating from a very old system - 5.5.... I'm going to stick with 7.4 which is new enough to be still supported and will satisfy the security gurus at work!
I've installed PHP8, but the only extensions I can see for SQLSRV are for 7.4 and below. I've tried enabling this extension anywyay, but it doesn't show in info.php
Does anyone have any ideas?