Hi Charliegal - it's funny 'cos I was kind of thinking the same thing this morning, in a grumbly unjustified kind of way!
My ds's are 5 and nearly 3 now so the 4 month stage feels a long time ago..! On the whole we've had brilliant experiences so far of playgroups, nurseries, childminders and school (have tested them all out! ). Some things keep cropping up - e.g. we always get asked every year about Father's Day, and what should ds's do, and every year we explain that they've got a Dad, see him often and so yes please he'd love a card!
Dp is building up a good network of getting to know other Mums (she's a SAHM, I work full-time) and the ones she's getting to know are lovely - ds1 gets invited on play dates and to parties and so far it's all good!
The most bizarre reaction we've had to date is my midwife in London, when I was first pregnant, who (when I explained our situation and introduced her to dp who was with me) asked me "is it legal?", looked horrified, left the room (I thought possibly to phone the police?!) and hardly spoke a word more to us when she returned. Fortunately we didn't have to see her again...
Anyway, I'll stop wittering!