BTW: A) You might have some private reason for not choosing NY I should have phrased my last sentence that you should could consider NY as opposed to asking why not.Again NY has many different neighborhoods where you might feel comfortable
B) I know a few former brits and they never felt fully comfortable with driving here.Regarding the above communities: Driving is usually a necessity and many families have two cars. In NYC you can do very nicely without having to drive you are never more then a five minute walk from shule shopping transportation.(taxis and transportation are abundant and cheaper in NYC then a suburban setting
C)Yeshiva tuition in NYC while prohibitive like most places is still less and easier to get a scholarship for then the above aforementioned cities additionally yeshiva school bus is provided.
For a special needs child Yeshiva tuition and/or day programs are given as part of govt grants for special needs.Outside nyc many municipalities require you to outlay some of the monies at the beginning of the school year and then petition for reimbursement(reimbursement does happen and they will cover tuition in the end but you must first register start paying tuition and then gov pays back the school after year has begun).
Hope we can be helpful and Hatzlacha with your move.