Any feedback on Mathnasium or London School of Maths and Programming

[Fancythat2015]

Hello, I'm looking at some extra support for my two kids - going into Year 4 and going into Year 8. Both are quite strong in maths.

Has anyone had any direct experience of either Mathnasium (esp. Chiswick in London) or the London School of Mathematics and Programming (LSMP)?

Tried Mathanasium (chiswick) and love that support esp if prepping for various entrance exams.