Which one is correct? Dates in scan

kiki • 💙💖💖💖💖💙(💛2023)

So I had a private scan at 8 +6 which dates me due the 2nd December 2019 but when we went to our OBGYN (hospital scan uk) a few weeks later when I would be 13+1 they actually dated me 12+5 which is a 3 day knock back. However the baby wouldn’t stop moving so I’m certain they’re measurements where wrong but now I’m panicking! I have my gender reveal scan booked at a private clinic and I’ll be asking them to confirm my dates but has anyone has it where they were told one date but due to baby moving measurements where incorrect? I’m almost certain they have it wrong and I’m actually due on the 2nd December not the 5th