Hi ChoccyMumma. I get these too, and ectopic (out of place) beats. Because I'm very over-attentive to my body noise and have health anxiety, they've been checked on quite a lot! I've had a 24 hour event monitor on twice (the second time, the private company the NHS contracted to administer those, lost my results and then they surfaced about 5 months later on my health record...) lots of ECGs and recently was referred to a cardiologist because an ultrasound identified a possible atrial defect (it wasn't). Nothing abnormal has ever been found - apparently I have possibly the high end of normal ectopic beats, but since the frequency of these is reliant on people noticing and reporting them, even that's hard to pin down. I am, apparently, one of those people who 'notice' heart stuff more than most. I find it really hard to turn off my attention to 'body noise'.
The cardiologist said my palpitations and ectopic beats were real because I was perceiving them, so it was a real issue for me, but not medically significant and that I'd have to learn to chill out about them. I have to say, hearing this did make that a bit easier!
I also find I'm much more aware of them if I lie on my left side (this is also normal) so I try not to. One thing I will say is, with the palpitations, sometimes I think what I'm experiencing is the perception of a racing heart - if I take my pulse it's not usually that fast.
Oestrogen depletion can exacerbate these symptoms and in fact, it was the main reason I went on HRT. Unfortunately, in my case, HRT hasn't really done much to get rid of them.