i've installed 2x of these https://www.toolstation.com/integral-led-lightspan-ip20-ik08-batten/p18251 in a customers garage about 15 months ago , so they've both been flickering here and there for 6 weeks now i've been informed. Anyway I was there today and they are working fine ,I tested the voltage at 243V ( the fittings are designed for 220-240) and made sure everything was tight, I also found were a few dead spiders in one of the fittings.
I'm thinking it's a voltage surge especially as both fittings have a flicker ( it's a flicker rather than strobing) I also thought it could be moisture in the air but the garage is completely dry. i've hopefully added a video there too. look forward to hearing any of your suggestions.