Hi Guys,
It was OK the next day after I restarted. I’m using a MacBookPro late 2013 (just prior to retina) with 8 gig so it’s not an all singing all dancing machine 
I’m so happy that this thing is on Mac and so happy it’s free for now to play around with. I used Rhino 4 a lot in two previous jobs as a designer - will definitely be buying myself a personal license when it’s launched on Mac.
I’m not too bothered with glitches
Cheers
Andy