Regent Street does seem to get pretty good lights. When I was a kid we usually went to London at Xmas. Another attraction was the window decorations at Selfridges. I remember there was one year we didn't go as the IRA were quite active. Of course I've taken my kids a few times too.
That place in Japan must have been used in a few films.
!BEER
I always try to find an excuse to go out to London around Christmas time just to get a feel of the vibe, but sadly it's a bit of a trek for me.
Tsumago is one of the most well preserved post town in Japan, I wouldn't be surprised if its always used in films