I would go for the UK Dark Green over UK Sky
Roger Freemans Mighty 8th Warpaint and heraldry book states this.
Frank oilers bubble top 'Eileen' was also in this scheme as were many others.
At the time natural metal finish P47s were being delivered.
The 78fg was recommended to add camoflage to these aircraft in case a move to the continent took place.
the book quotes
"Dark green from RAF stocks was used,but on most field camoflaged aircraft the undersurfaces were also painted with sky, the 78th was most consistent in this practise"
Have a look at
www.littlefriends.co.uk under 78th fighter group gallery
Hope this helps
Bwb