DW Runners

A few weeks back I had to stop running because I sprained my right ankle (mildly). It started feeling better last week so I went to the gym a couple of times and used the elliptical trainer, rowing machine and bike, but didn't run. Today I popped on my shoes and decided to try my usual pootle around the common. Because the terrain there is quite rough, I thereby discovered that my shoes are knackered. This may have contributed to my original injury.

I've been wearing the same type of neutral Brooks for quite a while now. (I don't overpronate.) The last time I went running shoe shopping, I bought multiple pairs because I really liked the shoe. This, however, was the last pair. The label is so worn that I can't even read it to remind me what type it was. In any case, it's quite clear to me that I need new shoes. I have a few questions that I was hoping some people on this comm could help me with.

1. Trail running shoes often seem to have black soles. I use the same pair of shoes for the gym and for running outside, and while my gym doesn't explicitly ban black-soled shoes, I suspect they prefer white-soled ones. If I choose trail running shoes, are there any white-soled options?
   
   
2. UK-based runners: Do you have a favourite online shop for shoes? Or a favourite actual shop that might have a branch in London or Cambridge?
   
   
3. I've always worn Brooks shoes. Do you have a preferred brand? Is there any reason I shouldn't be wearing Brooks?