OK, got it... found these two posts when I searched "exclude" as I figured I was either missing something I should exclude or vice versa.

#4195
Hi can some please help as i have a problem with my cart. I cannot remove products from the shopping cart. Has anyone else had the same problem ???

Many Thanks
#4196
Sorry i just found it. I didnt look hard enough . Lazy me.

Re: Simple SEO URL [support thread]

Ah, you meant remove to cart. Yes, the quickest way to fix this is to go to the admin config of ssu and put shopping_cart in the page exclude list.
This fixed it :)