If you're going to stop at Bunker Bier Hall, I recommend doing it before going to Belgo Centraal across the street. Brewpubs are few and far between, so this was the only one I had a shot of doing on my short trip to London, but I'm glad I didn't go far out of my way.
The downstairs bar was dark and seedy, and a lot of young, hipster types, mostly drinking cocktails and malternatives. Only about a third of the people I saw were drinking beer. I wasn't expecting much after reading the reviews, but the bartender warning me that the Soho Red is more of an ale scared me--rightfully so. I sat and drank the astringent red with little body for a bit and decided that it wasn't worth the effort to finish, so left it sit on the table and walked out. Guessing that if I had tried some of the lagers, I would have had a better experience, but at three pounds a pint, it adds up fast with the poor US currency rate, so $6 dollars seemed too high a price to test my theory when we were running low on pounds near the end of our trip.
Oddly, at the Royal Oak, I met Richard, who said he is a rep for Freedom beer, and that he was sad to hear my negative experience. From the discussion, it seems that Freedom is working hard to improve and brew good beer. Maybe the lagers are better; maybe I had a bad night. My very short experience was not good, but probably also not a fair test. I wish them luck.
4/18/13 update. Website is down and one source said this brewpub is closed.