When was the Oxford HMV CD signing accounced?

[twinmatrix]

In 2011 Stevie did a CD signing at the HMV at Oxford Circus in London. I'm wondering how far in advance this was announced?

I'm a bit on the fence about attending the Hyde Park concert because I just booked a flight to see her in Newark, and she will visit locally with Fleetwood Mac anyway. But if there's a chance she will do a CD signing / meet & greet then I will be sitting at the HMV with a camping tent 10 days in advance tbh.