Ah so I'm not the only one thinking I've gone mad! I have white scenery on tracks and platform too but bizarrely other landscape scenery seems to be green or as it was before.
There is also a yellow box saying "missing textures" that is sometimes visible when you use different views when driving on the PDL.
However...not sure if it is just me, but when driving 450's the acceleration is now much faster than before even up to 90mph, great you might think, however the breaking is now very weak. There must be some sort of error with the update as even on 100% emergency breaking it takes about 60 seconds to come to a stand, usually I started breaking when 0.5km from a station at about 30-40% however this is impossible now, needing to break at 83% over 1km before the station!
Is there any way to reverse this? I much prefered how the PDL was before? I have tried clearing "blueprint cache" however this option is greyed out and even followed Railworks instructions to "verify" all files and no error was found!