Hi Rebecca
My father is midlands based, I'm afraid. However I reckon that going the conservation route is probably unnecessary for this work. It's not a museum piece and these types of drawings were common enough at that time. Just go to a local framer and have it mounted and framed, the glass and board backing alone will keep dust and dirt at bay, should cost you about (is this A1 size?) €100 depending on size. Unfortunately the colour will fade in time especially if exposed to direct sunlight. These drawings were never destined for permanent display I imagine.