Just came back from a training about enterprisedb, a flavour of PostgreSQL with complete Oracle compatibility. Never heard of them before, and had a good surprise : 3 of the 7 pgsql core team members are working for them. They are the guys that designed the WAL system which finally made PostgreSQL an enterprise class database (at least for me). Their implementation uses a pretty cool dynamic tuning system to get a correct PostgreSQL setup for your server with only one setting.
Side note : London is a very expensive city, 63 pounds to go from heathrow to town center by cab, 4 pounds for an underground ticket :/