Please help me find the best version of this necklace

[Plonque]

I've coveted a necklace like this for a while and now I'm just thinking - sod it! ... I'm ready to treat myself and part can be from dh cos he keeps asking what I want.
I know it's a popular style, I'd ideally like real diamond. Have you seen one and can point me in the right direction..? Please!
Budget up to £400

link to the one I've seen on Etsy

Initial that I actually want is K if that makes any difference

I found this company,

London Road jewellery. They have some nice pieces in the 400 to 500 range too. I have no experience of shopping there though.

link

Thanks! I'm just perusing their site now