Doppler?

Hannah • Albie, 4/4/17 💙✨
Hi I am currently 12 weeks 3 days and have my 13 week scan on Friday. I have had 2 previous scans and still not heard the heartbeat and don't expect to on Friday. My last scan I had the sonographer told me I won't hear the heartbeat until I see my midwife at 16 weeks, is this norm? I am in the UK? I am also considering buying a Doppler but wouldn't know where to start looking? Any advice would be great 🙂 FTM also.