Larry,  I apologize, I thought this information had been given to you long ago:  Executive Relocation in London (outside service we use for cases just like yours); contact is Hanna.
They should be able to answer your questions related to housing opportunities, availability of medical services and schools.
Their number is 44 20 7792 7511.
Also, our HR contacts in London did speak to another Enron family with an autistic child and they said they would be happy to speak to you about the school they chose, availability of care, etc.
The Jacobson's (Steve and Cheryl) can be reached at 44 207 384 0720.
Thanks,

Contact Information in London