I had a mailing from the South Bank Centre today. All their phone numbers are now in the 0871 663 25xx range. Previously many of the SBC numbers were 0870 but they obviously want a bit more revenue. The charges for the 0871 numbers are not stated anywhere on their literature.

The geo 020 7921 0600 still connects and has an option for the box office which I have not actually tried.

They are also raising their membership scheme from £10 per year to £25 for some vague extra benefits. They'll have to be pretty good for me to want to stay a member.