For the past 3 or 4 days I am 99% certain I have been feeling movement in there.

Always before bed and first thing in the morning. It's more of a tummy rumble (though I don't feel hungry and eat my main meal mid evening then have breakfast around 9.30 and I wake before 8am) It's a familiar feeling like before. It's quite unmistakable.

They do say you feel movement earlier in a second pregnancy but I'm incredibly happy all the same.