The day has come and gone. A pub in terminal 5 (Wetherspoon's Crown Rivers, I think) has rotating hand pull selections and I got lucky: London pride, Fuller's ESB, and Adnam's all there! Three of the four I had wanted (TT Landlord being the other). Everybody seemed to be drinking Adnam's. It was excellent, and I could have drunk it all day with the right friends. The LP was pretty good; a classic english bitter taste, but not as interesting as the adnam's. The esb was a let down. Considering this is a favorite beer of mine in bottle, I expected much much more. Maybe it was just getting old. Hard to tell from a sample size of one.
So the local experts were right, six hours proved to be dangerously close to get into London, largely due to the fact I would've actually only had 4.5 hours once I got through immigration. Plane was on time; but I was in just about the last row, we had to wait to get on buses to transport us to the terminal, and the queue for immigration was enormous by the time I got there.
On the return trip, I stopped in and the three ales listed above were gone and replaced with ciders. Good I'm sure, but not my preference, so fortune smiled on me that day.
In Berlin I stopped in to the Standige and had some Gaffel Kolsch. It was decent and drinkable, but I could easily imagine that other Kolsch brands in Koln are better. Will have to find out some day. It was also great to have fresh German wheat beer for a week.