Have been doing XP with a team of 10 developers at http://www.securetrading.com for almost 2 years now.
We mostly use Python with some Java for client side apps.
In previous lives I've been involved in medical diagnostic software (http://www.dpcweb.com/) and a machine for running Smalltalk effectively (http://www.wolczko.com/mushroom/).
I'm particularly interested Agile Methodologies and their application to other business processes.
Im actually WestOfEngland, but Warrington is closer than London.
mailto:ifor.williams@securetrading.com