I know three people with children there. One mutters under xxx breath about clubs not running despite the puff on the website, one mutters about some problem teachers not being as dyslexia/spLd aware (of dc's needs) as they should be and the other raves about the school.
I can tell you that the Admissions dept. was shockingly unprofessional (and very nearly useless despite being pleasant) to a friend of mine although that friend was advised not to take too much notice of them as they don't necessarily reflect the school in general... although maybe they do in some quarters. A big black mark for a school charging around £30K a year.
The special needs coordinator, the same friend said, was very good though. Just not sure it filters its way around the school to 'all' teachers the way it should.
The challenge grade system is a good innovation and worth looking at.
There are other better schools out there that don't necessarily promote their learning needs support as a USP but are nevetheless much better imo.
My overall impression is that Seaford sits on its laurels a bit in terms of what it's known for (and given how desperate parents can get for the dcs to get support if needed). Undoubtedly, it has some great departments, DT for instance, but beyond that, it really is a case of looking through the puff and considering other schools who don't promote that side of their work but may in fact do it better.