I'd like to take MIl for a day or half day to a nice spa in London. It's a big birthday (she'll be 70) so I'm looking for somewhere luxurious but, as she's very shy, not somewhere where she will feel awkward.
I went to the Sanctuary many years ago which was nice enough but I'm sure there's much more choice these days. I'm in South West London so anywhere in Central or SW London would be fine.
Please give me your best suggestions!