......the whole centre section is grey and the edges are bright with some faulty individual LEDs apparent. Life is quite short for these if used all day.

Where I used to work, when I started there the workshop lighting as 400W mercury vapour lamps - 20 of them. Lamps lasted well, but were pricy to replace and if the power went off they had to cool for 10 minutes before they would restart - and they were 400W each.

So I removed the ballasts from the lamp housings & replaced the mercury lamps with 150w CFL "growing lamps" that used the same ES base. Near instant start-up and, when new, too bright to look at. After around 2 years they need replacing, as they had gone dim, but cheaper to replace than the mercury lamps (and cheaper to run).

Next swap was to LED "corn cob" lamps designed to replace the CFLs - quite a bit pricier than the CFLS but a small energy saving (125W) and, when installed, as bright as a small sun. After a couple of years the indivdual LEDs were clearly "burned" in the centre and the lamps needed replacing again.

As the "corn cob" lamps cost more than CFLs & didn't last any longer I went back to those. Biggest issue was getting them delivered in one piece - in one instance every one of the dozen lamps in a case was broken on arrival, as were the contents of the replacement case.

Disingenuous marketing doesn't help with either CFLs or LEDs - the quoted "life" isn't a "mean time between failures" but an indication of operating hours until the lamp output reduces to (typically) 50% of new. Still working, but need changing because they don't work well enough. And I bet most won't get recycled but go straight to landfill.

Bring back mantles !

Nigel B.