Hi all, and thanks for the feedback!
I've done about 300 miles now and the engine is noticeably smoother (it was previously noticeably LESS smooth than it had PREVIOUSLY been, if you get me!). It also feels much sharper. I don't mean +10bhp or anything like that, just more willing generally. I don't know about mpg yet cos i've got a few days off work while i do ARB bushes and oil change but initial impressions are promising.
I've also worked out that it's SIGNIFICANTLY cheaper than using BP Ulimate!!