They're very rarely open on Saturdays (or Sundays. I thought it was a ghost pub at first because I only ever seemed to pass it on weekends and it was always shut). If you can push a longer than usual lunch break, then why not try get down there today?
I've just been to the Oak this evening and it was overrun by suits. It seems a company has just moved to an office nearby, and the Oak was their celebratory venue. Horrible cigarette smoke was being whafted into my face, and cigarette ash flicked onto floor and the rugs - and most of them were drinking vile tasteless stuff like carling. Jessie - the resident dog - didnt seem to like them either. They made the toilets smell too. The food was excellent as normal, though. Just a pity the atmosphere was ruined. I do hope they don't stay.