The results speak for themselves - BW is the top non-selective school and 6th form in Bromley Borough with 82% getting 5 A-Cs incl maths and english and 66% of A-levels at grade A*-B last year and an average point score of 359.52. They got an outstanding OFSTED last year too. in short, I don't think you could get a better fall-back school and many choose to send their DDs to BW rather than the Bexley and Kent Grammars.
Will PM you with more detailed info re the standard of teaching etc when I get time (could be next week
HTH for now