University of London Institute of Education - a good place for a PhD?

Two of my colleagues are currently doing part-time doctorates in education with the IoE and they invited me to an event where IoE students in Tokyo presented their current research. Professor Paul Dowling was there to answer questions too. I got a chance to ask several people, including Paul, about the process of application and the "tortuous" challenge of getting the disseration done, especially on a part-time basis while teaching full-time.

Most of the advice I had heard before, but it was good to hear it again:
-Make sure you know what your research passion is
-Design a small, realistic project for researching that passion
-Try to find a good supervisor for the research
-Make a solid financing plan
-Be ready to dump your social life and neglect your family (My interpretation)

So, Mark, what's the plan? Decisions, decisions.
-I have many research interests, but what's my research passion? How in the world do you decide that?
-Which school is best for that research area/approach?
-Do I go full time (and break the bank) or go part time (and try to balance job and degree)?
-Do I go to a US program with course requirements (which I kind of feel I need), or a British program which is mainly just the disseration?
-Do I wait until...

Mark