William (Bill) Lambert's painting of Great Tew from Iraq

I would like to show you the picture that my uncle Bill and Auntie Doll had on their living room wall in Lambourn, Berks. It has since become damaged by foxing from damp storage, sadly. All I know is that Uncle Bill was in Iraq in WW2 and he brought this painting home with him. A fellow soldier had painted it from a postcard of Great Tew. How did he get artists' materials? Did he take his paints with him? It is an image of extraordinary nostalgia for England.