thanks, how?
Launch Setting
General
Home Button
Spotlight Search
Deselect indexing for all or as many items as possible
Just done it, still takes 6+ seconds to open my SMS inbox.
HOWEVER, it does speed up the rest of the phone no end. I'm impressed, more so because I don't use Spotlight for anything so it's a no lose for me.

Thanks SilverPenguin, much appreciated.