Yesterday I tried Cabot Square, which is very sunny, but rather crowded and thus not great for a meeting point unless we go early. I'm going to check Jubilee Gardens today, in case it is easier to take over an area there (at 12.30, should people who know me be free). If anyone can suggest a better sunny spot with slightly fewer crowds, go for it.
Otherwise, I plan to be having lunch in the sun tomorrow, probably in Cabot Square, at 12. I'll be there for an hour.
Hope to see you there.
ETA: Jubilee Gardens was much nicer, and we can meet on the grassy knoll, as a bonus. Still at 12, though, I think.
The gardens are right next to the main entrance of the Tube station, more or less above the food court.
There is a hillock to the right of the green area as you come out of the shopping centre, or at the back left of the garden if you enter from the Tube side.
I have a small picnic mat which will make me easy to spot, and I stick my stuff in a blue shoebag. I draw the line at carrying a copy of the Times and wearing a carnation for identification purposes.