From Senior's tales of his time in Enniskillen (1950-7), it's clear that few coaches saw a paintbrush at all during that time. No. 4, also a favourite of mine, did get a repaint and so did one, possibly two of the trio of bogies.
However, they were kept outside. My own experience with repaint of wooden bodied coaches at Whitehead in the pre-carriage-shed days were that rapid deterioration took place in such circumstances, with paint beginning to peel after as little as two years.
I could see the SLNCR being embarrassed, and blaming a wagon painter, but the real culprit was the company's dire financial straits. Senior recalls "ballast" trains consisting of a wagon of ashes and cinders from Enniskillen loco shed attached to the back of the goods, which stopped at the required spot to shovel it off.....