Digitally re-master & enlarge a painted Ceiling Image

I would like to create a life size (5.15m x 6.7m) remastered digital version of this painted ceiling image to look as close to real as possible.
The image must be in plan form of the painted ceiling section only (an exact copy of the artwork, not a copy of the photograph)
The colours are a little tired and could be intensified / brightened up a bit.
The resolution would need to be good enough to not show any pixelation at a distance of 2m.
Additional Photos can be viewed on :
https://www.dropbox.com/sh/ph68vndt716q87g/AAAIEjT50u6vd-y_v6w2vq-8a?dl=0