It would be interesting to determine whether the kids availing of free swimming are generally better off and also whether the pensioners tend to be the less well off ones.

I think research on swimming in schools generally shows that your ability to swim tends to reflect your socio-economic group or cultural background and so free swimming probably benefits these people more whereas spending money on lessons in primary schools will tend to benefit all and especially those children from less privileged backgrounds. I would say though there is a strong argument to keep it for the secondary school kids and perhaps link it to the zip card as these kids regardless of background should have the chance to swim or mess about in water which they won't get in school.