Taking you at your word Davel
I will ask my mum and dad later today-as this was 10 years ago he found the locket. They are very down to earth no nonsense people!
I discueed this with my parents and this is what they recall:
Mum. We were all talking about xxxxx as we usually do at our family anniversary, J mentioned she got a new tattoo and a necklace for her Birthday previous week, I said it looked like the one I had and xxxx wore it on her death day. YOU (me) said what about that, I said oh I think it got lost with the belongings given back from police,you said what got lost- I said my necklace that xxx was wearing. You went into the kitchen and stood very quiet for ages. M asked what was wrong and you said It may be under the driveway I said how could you know that, you said you didn't know she was wearing it. M and J came into the Kitchen we all discussed the possibility but couldn't believe it got under the mono block, Dad made an entry and said oh there was a crack on the drive where the car is parked that is why we got mono block on one side of the house. M&J and Dad Went outside and removed some bricks where the cracked paving stone used to be and found the locket! It must have fell of while you were playing chase.
I have no reason to make this up, I could have not typed anything and spared any ridicule coming my way. I just thought I would anyway.