Here is my try. Getting rid of the light was quite easy but the 'halo' effect on the guys hair is more difficult. It still showed after doing the wall re-colouring.
Anyway for what it is worth, here is my approach:
1. Used colour picker to get the targeted wall colour
2. Then just brushed the lighted area and blurred for effect
3. Selected the blurred area and erased excess as required
4. Duplicated the layer and set reduced opacities (90%) and used Normal mode for each.
5. Selected the colour of the wall corner and on a new layer drew a dark line to reinforce it up to the ceiling.
6. Still had the halo effect of the light on guys hair – tried following actions to fix.
7. Used colour picker at base of neck to establish his 'real' hair colour
8. On a new layer, brushed that colour over all of his hair.
9. Set the hair colour layer to Overlay at 100% opacity.
There is still slight evidence of the halo effect around the top of his hair, and also there is some light on the girl's uniform, so whether to try further to fix these is up to you
