The hardest thing in these cases is always conveying that the color of the surfaces is from light, rather than paint. A very delicate balancing act.
And to compound matters, in the spaces themselves that distinction is not always so evident, those darned stained glass windows throw countless different color casts amidst the overall low light. You almost have to impose a more luminous look by rebalancing the apparent lighting, implying that the sun lighted areas are rather light, luminous tones rather than the mid tones they really are. And I can see that you are pushing in that direction. Was so much easier with black and white.