I always take the view that if something is marked on my chart, it is there for a reason. I do believe instrument approaches outside CAS are marked on the VFR half mil charts. That said, I've had a discussion with an instructor (I was P u/t) about the merits of flying over the Cranfield FAF (CIT) at 1500ft; he was of the view that it was Class G so crack on.
PS. Newton's Laws don't give two hoots whether you are flying a microlight, SEP , MEP or something far more exotic.