i remember going to a place called blackbird farm. this was a good few years ago though, and i dont remember where exactly it was, just know that its in herts. maybe google for that? other than that, i cant think of anywhere else, sorry
There is a PYO on Harpenden Road on the left going from St Albans to Harpenden just after Rugby Club fields and before Childwickbury. It's good. Sorry, don't know name though - it's usually open when I drive past during the day.