12 and 20 weeks is normal.
with my dc I had
dc1 - 9 weeks due to bleeding. They cancelled my dating scan because of the 9 week scan but I begged the midwife to still let me have one. 20 weeks, 22 weeks to check baby's heart, 35 week growth scan.
dc2- 10 weeks dating. 20 weeks. 30 weeks to check baby's heart. 32 weeks sneak peek when they were scanning my heart.
dc3 - 17 weeks dating, 20 weeks. 22 weeks to check baby's heart. Growth scans at 24, 28 and 32 weeks
dc4 - 12 weeks dating, 20 weeks. 22 weeks with fetal medicine, 24 weeks growth, 26 weeks fetal medicine. 28 weeks 3d. 32 weeks growth. 35 weeks twice to check position of baby.
dc5 - 12 weeks dating, 20 weeks. Growth scans at 28, 32 weeks. 2 scans at 35 weeks to check position.
All nhs apart from the 3d one with dc4 which was paid for by a charity.