Witch - I love the way you tell us you've made a phone call re window bars and then in the next breath invite us over for afternoon tea
It gives this image of us all sitting there while someone in a stripy jumper tries to steal our cake.
Pez - that's really kind of you to think of me 
I would hate for you all to make plans so that I can join you if then I'm not in a fit state to come along, especially because (due to my hip) traveling is difficult so I need to be realistic about where I could get to.
If I did join you it would need to be somewhere I can get sensibly on public transport (unless Stork happened to be driving and could collect me en route) which basically means somewhere within walking distance of Euston or one of the stations on that line (Harrow, Bushey etc.) Regent's Park springs to mind, but that could be a royal pain in the backside for other folks to get to so I don't want to make you all do that!
Normally I would happily drive to Hampstead Heath but my hip can't do stop-start traffic.
I think it might be too complicated for me to join you this time but I'll see how your plans unfold and if I can join you I'd love to!
The other issue of course is that some of you might currently be in a place where you don't want to have to spend the day with me and my undisguisable bump, and I don't want to make anyone feel sad with my presence!