PM answered.
I reproduce it here so other modellers may benefit.
to cover the D-Day Landings until after the Caen then there were two seperate shades depending on the vehicles age. New Vehicles from May'44 had this base coat
The DAK alternative is RAL 8000 VMA 71.272
Older vehicles would have the previous variant
DAK RAL 7027 VMA 71.118
This was noted by allied army intelligence that there were two seperate shades with the newer and "brighter" (RAL8000) seen on Panthers and heavy armour arriving at the front. 21 Panzer had the previous base shade until new vehicles arrived to replace losses (Pz IV)
Things didn't change until January 1945 but the last variant of RAL 7028 was trialled in Hungary during operation Panzerfaust in October 1944 by a few Tiger II tanks from the 503. you can see this in photos taken that the base coat had changed to the green and the tanks look decidedly darker. Ignore the "colourised" pics and stay with the original B&W.
The Base Coat changed to RAL 6003 Green and the last variant of 7028 was used as disruptive camo.
DAK RAK 7008 VMA 71.116
Until Vallejo get around to releasing the proper stuff then this is the closest and I personally think that very late war some of these would have been used as substitutes due to shortages etc. There's no proof as yet.
We just have to wait until things "normalise"