My son went to Ashcroft. It's a good school but doesn't suit everyone. It's very strict and they dish out a lot of detentions to get students in line, which can be a little demoralising for students at times, especially new ones. I work at another school and we always get a few in year transfer requests from Y7s and Y8s who have gone to Ashcroft but can't hack the discipline.
I found the approach of the school quite cold - from Head's talk to contacting reception - and they can lack the human touch sometimes e.g. giving my son a 15 hour catch up detention for missing two days of school to attend a family funeral out of London. They get good results though.
They were excellent at supporting my son through his GCSEs and his Head of Year in the upper years was great. Go in with your eyes open as if a student isn't making the grade, they won't be kept on for 6th Form which can be a shock for some parents (and students).
We didn't send our daughter there as it wouldn't have been the right school for her and she didn't like it when we looked around but we are glad our son went there. He didn't stay on for 6th form out of choice as he wanted a change and to go to a specialist Sixth Form.