Blame it on the cheap doppler. A lot of those that are sold online really cannot detect fetal heartbeat until the baby is much much bigger.

thank you everyone! You've really put my mind at ease. It is one of those ones with earphones too Wobbles! I'm usually a UK size 8/10 though so I don't think it's the obesity issue that's messing things up...at least I hope not...unless I've really put on weight! My scan got brought forward anyway - a week today I will have either seen a baby or a not-to-be baby!

Thanks again x