I got my visa in Edinburgh (I work there 3 days per week) and although there were several people with the same appointment time I turned up about 5 mins after my appointment time and I was number 003 so waited something like 5 minutes. The Edinburgh office doesn't sound as busy as the London office.

It appears that I was lucky though as a colleague did the same thing and had his application rejected as he put down his London address so was told that he had to apply via London. I put down my Kent address but I guess they didn't know where that was so I got away with it!

I can confirm how pedantic they are though. Another colleague is called Jo and her letter of invitation stated Jo. However this was rejected because her passport says Joanne, so make sure that your full name is used on all of the documentation and matches your passport exactly.