Hm. In my experience, -eigh has always been pronounced -ee. In most cases, Leigh is a homophone of Lee, as it comes from an English word meaning “meadow”, and you’ll find many pronunciation guides that confirm this. Not that I find it all that intuitive, I would have assumed it to be pronounced -lay myself, like sleigh or eight. English is dumb like that, and if you or anyone else wants to pronounce it -lay, nothing should stop you.