Sandown this weekend 15th/4th

Hi all, I'm keen to go look at some circuit racing and I see that CAMS is holding a license test this weekend at sandown. I will be heading down that way this weekend anyway and was thinking of popping in and taking a look, I do realize it's not going to be the real deal but its something. My question is will I be allowed to just go and spectate? Also do they get many cars to these things or will it just be a handful not worth watching?

Thanks