Somerset House a little while as they were setting up the outdoor ice rink. It wasn't yet open but it had some people skating nevertheless. Unfortunately I found it completely impossible to find anywhere you could see what was going on while outside - so retreated back inside Somerset House and found a staircase with a window which let me look down on the rink and the skaters. However it did mean I had to sketch standing up which severely limits my sketching time so I think I need to get out and see a few more rinks!
Judging by the photograph on the Somerset House Ice Rink website I maybe ought to try going back after dark!
The best rink in London for looking down on skaters is the one at the Natural History Museum as it has a great viewing platform.
The other one I can get to easily is the ice rink at the Old Royal Naval College in Greenwich - but that's not taking place this year for some reason - which is a pity as it's a good one for seeing skaters up close. See Boxing Day ice skating at Greenwich