thanks for the responses, its good to know its not just me or the way i setup my PC.
Tonight [time permitting] I'm going to try something as I think but aren't sure that when i first enabled AHCI and Vista loaded its own MS drivers, the pause didn't exist but shortly afterwards I'll have updated my Catalyst drivers which these days iirc also contain the ATI AHCI driver. So I'll re-run the Catalyst setup and uninstall ATI's AHCI/Sata driver and see if the pause disappears.
If it doesn't then like the rest of you with this, I'll not lose sleep over it

but I do like a PC to boot up fairly quick and mine would be fairly nippy if it wasn't for this.