Whistle, I'm not a massive fan of extended BF myself but I respect other women's rights to do so if they choose. I would probably think it a bit weird to see a 5 year old BFing in public but I don't think they should be asked to move on or stop any more than a mother with a baby.
As for at the pool, just sit out on the side? If a feeding woman swims she might leak into the water anyway and if she didn't have her child with her how would you even know? I think there are far more unsanitary things that go into public swimming pool water anyway...
I think they are trying to extend the rights already vaguely lent to feeding mothers to include bottle feeding and for an extended amount of time (England has only civil law, NI has no properly defined law, Scotland only serves until the child is 2 according to details on the page).
It's not something I ever had an issue with though I rarely fed in public but I think if I had been asked to leave somewhere (for instance) it would have been nice to have something solid like "It's against the law for you to stop me feeding my hungry child here" would have been nice to have. Anyway it's here for anyone who would like to sign 