to reply to both issues, with your help I've solved the array autostart issue. It was an external eSATA Raid enclosure that was causing the problem.
I've removed it from the array, and the autostart is working properly again, (although I'm at a loss to explain why, as it was working fine before).
As to the slow WebUI, I've narrowed it down to the "Unraid Connect" plugin... After installing it, the slow WebUI issue returned... I uninstalled it, and
the WebUI response time went back to normal... obviously there is an issue with the "Unraid Connect" plugin.
Finally figured out the issue! Turns out the power supply was the problem... I guess it's time was up...
Replaced it, and so far, so good! no more random lockups....