The biggest of boys in Soho are probably places like: –
The Mill
Framestore CFC
Rushes
Smoke & Mirrors
VTR group
Some of those (Mill & Framestore esp.) are mainly film-based, but I think both do some TV aswell. You’re probably looking at Inferno/Flame or similar for a main VFX/Compositing position, then I guess a few seats Shake/DF/Nuke/poss AE for support work?
Good luck, as soon as I decide that London is no longer an ugly prospect to live in then I’ll probably end up tapping at their doors aswell! Meantime I’ll stay on my more modest jobs up here in the North!
Jim.