Is this a correct diagnosis? Brown leaves with white spots

[PeteB]

Thank you for the replies, I've attached photos of the roots as requested - to me they look OK but perhaps if I were to take the moss away I might reveal more issues.

Before I took on the plants it was on a windowsill that may have been South facing but this was 4 months ago. I might have remembered incorrectly and the leaves may have already been damaged, but I don't remember it being this bad or with white spots.

It's currently on a windowsill facing north and I'm in England with cloudy weather so I'd imagine it's unlikely have been sunburnt here. Possible, but unlikely.

The leaves with the white spots still seem fleshy but watery and they seem very similar to bacterial infections shown from other peoples images online so I can't help feel that it's more likely this, at least as a secondary ailment caused from sun damage as Ray suggests. Of course I do regard all your expertise higher than my own opinion!