BDA
In an Educational related context, BDA can stand for British Dyslexia Association
The top of the list in my Google search; BDA is British Dental Association
And a couple of others: British Dietetic Association and British Deaf Association.
There used to be a British Diabetic Association but that's now Diabetes UK. They made a sensible move, I think. Take a look at the web addresses of the other links that I gave...
bda.org, bda.uk.com, bda.org.uk (OK the Dyslexia one is bdadyslexia.org.uk)
This is why I hate acronyms. I get confused by acronyms. I feel excluded when people speak using them. Why make an acronym? (Yes, MOODLE is an acronym (so is LASER). They have morphed into words.) My argument is to beware of using acronyms lest they confuse. Nuff said.