Bought for my daughter who is studying French at GCSE. The school was selling them for more money than Amazon (which I find pretty disgusting) so I bought them from Amazon instead. Weirdly enough, the Science revision guide's the school was selling slightly cheaper at £10 for all 3 sciences.
She's only just started with these, but they must be doing well as she aced all exams (not the full GCSEs - just interim ones) with an A in everything, except Math's where she got a B. Pretty good though.