I had a very similar experience last August. I found broken porcelain in my club world meal from LAS. I spoke to the CSM who said he’d report it but I heard nothing further. I did however take pictures & kept a sliver of the broken dish

I made a formal complaint through BA.com and heard nothing for over a month & contacted them via twitter. They came back to say the issue had been investigated and there was no evidence of a problem. When I told them I had pictures and a piece of the porcelain they changed their tune. “oh we’ll need to pass this to our legal team”

Three months went by and I continually tweeted & emailed them. Eventually in late January I was contacted by a very apologetic gentleman who offered me a voucher for £300 (not sure why that figure). For me it was never about compensation so I accepted without argument

The fact you have no “evidence” leaves you in a difficult situation. You could threaten legal action but don’t know how far you’ll get & I doubt any media outlet will be interested as it’s your word versus theirs