Thanks @Skye that's reassuring!! But would have thought the sonographer would have had a better idea of these things, it's odd that she volunteered a fairly strong opinion of her own volition if it's so hard to tell (we certainly didn't ask her to!). She was comically rude, when the baby appeared and was turning somersaults and doing jazz hands I started to laugh and she snapped, "WILL YOU STOP THAT, please, how am I supposed to do this when you are BOTH moving?" !
To be honest, I was so worried about the health of this little one that I skipped out of the scan this morning thinking it was a healthy boy, but if I was forced to choose I probably would have picked girl. I would like to have a girl at some stage - would be equally happy with boy/girl, or two girls, but if I'm honest my preference would be that one of my children be a girl so not two or three boys, so I'm delighted... feel a bit sexist having a preference as I am a feminist, but I like the idea of raising a kick-ass girl!