On Mon, 4 Jun 2018 15:07:55 +0100, Brian Reay wrote:

So, I'm considering LED replacements.

Just swapping the tubes (removing the starters and 'choke' is part of
the process I believe) is an option, as is new fittings.

The simplest is swap tubes, replace flory starter with LED "starter"
(ie a bit of wire in a starter housing), job done. Also easy to
revert to florry. Or you can remove/bypass the choke and power factor
capacitor and just have mains L & N to one end of the tube holder.
Put a florry into such a modifed fitting I suspect the filament in
the end with full mains won't last long, both ends are normally in
series across the mains...

However, I'm concerned about achieving enough light.

The existing tubes are 58W which, seem to give 5500 or so lumens (based
on an internet search).

I recently swapped out some 5' 58W florries for 20W LED 2000lm. I
think I could just tell that the LED was lower light level when I
swapped but in normal use I don't and there has been no comment about
light levels from SWMBO'd.

Remember that your senses are log not lin, so half the power is only
a 3 dB change which is generally accepted to be the smallest change
you can detect.

--
Cheers
Dave.