Forgot to let you know how my 20 week scan went yesterday... Copying and pasting what I put in the Facebook group 
Scan was great although we had a "VERY wriggly baby in a VERY VERY awkward position" (sonographers words!).
She managed to measure everything except one thigh bone and the heart so she asked me to go for a walk, have a drink and come back after 20 mins.
Nothing to worry about as she could see the heart beating fine and she could see the 4 chambers and both ventricles... She just couldn't get a decent measurement due to the angle of the baby.
Anyway... My walk and drink didn't achieve much as the baby was being just as awkward when we went back although she was slightly more satisfied I suppose as she managed to get the thigh measurement and was finally happy with the heart......although she had to do an average measurement based on looking at the heart from a few different angles (all the angles except the one she wanted basically!).
Anyway... We didn't find out the gender but she said the baby was being so wriggly and awkward that she probably wouldn't have been able to tell us the gender even if we wanted her to. because the legs were curled up under its bum for 99% of the time!
She also did a transvaginal scan to check my cervix to make sure it wasn't short...
Apparently short cervixes can cause premature birth? Well my cervix is "lovely and long"... Which is nice ??
In the end she gave us 6 scan photos and didn't charge us at all because she said she thought they were a bit crap because the baby was moving so much! But I actually think they're great photos so quite happy with that!!!