4D scan fail.

So today I went for a 4D scan paid for privately and my little boy wouldn't move his hand from his face, I was set to run up and down the stairs to see if he'd move came back into the ultrasound room and his foot was in this mouth. Went back an hour later and still baby in the same place. We've been offered a rescan for 2 weeks time and I'll be 28+3 when I go for my next scan. Can anyone post their 4D scans from this gestation and also give me any tips as to how to get my baby moving in case this happens again?