Best boarding schools in Bangkok?

Hi I am looking for a weekly/full time boarding school for my 12 year old daughter in the vicinity of Bangkok. Ideally one that is flexible to provide full boarding when I am traveling and weekly boarding when I am not - if that is possible?
I am would prefer IB or American system but possibly IGCSE. I am looking for a western run school with at least 30% western pupils and at least 80% western teachers (that's just my preference and would not be for everyone I'm sure).
NIST and ISB have been recommended but they are not boarding schools. I saw the following on the web: The American School BKK - but I'm not sure how American it is or how good it is? I also saw on the internet the following British type schools: Bromsgrove, Harrow and Regents - can anyone tell me if they are any good and does their affiliation to the UK schools mean anything in practice?
Any recommendations or frank opinions would be much appreciated