GB wrote:

I bought 4 of these for our kitchen:

https://www.amazon.co.uk/gp/product/B0895H85RF

3 of them have failed, and Amazon have agreed that I should return the
lot, including the replacements I bought.

They are circular panels (36W 3240LM 4000K). In retrospect, they are a
bit too bright, so I'd settle for lower wattage. These ones allegedly
have a 20,000 hour lifespan.

Can anyone recommend some reliable lights that look similar, but
actually work, please?

I've bought a few of this type

https://www.ebay.co.uk/itm/recessed-LED/291235836793

not from this seller and I suppose with such commodity items from
ebay/aliexpress/amazon, there's no guarantee the same supplier supplies
the exact same items even a few weeks later, but they haven't broken
down ...