Thank you very much for all your replies. There is plenty to ponder there. I will let my sister choose, as she is travelling, not me.

To Colin Rosenstiel, who wrote:

"Croydon's a big place. Whereabouts there?"

Not that it matters, but I live more or less opposite South Croydon railway station, so it's a relatively short journey to Victoria, and the Whitgift Centre is a mere bus ride away.