[landrovered]

Are you pulling the plugs and fogging the cylinders with oil before storage?

Also yours is a bit of a trick answer in that the stricter the temperature control is the less formation of condensation there is inside the engine. Also long term storage involves desiccant packs to remove moisture from the air which encapsulates the vehicle in a plastic bags or pods.

Secondly the oil may as well be in a can if it just sits in the sump, It will not degrade if it is kept at a constant temp and humidity and the surface area is limited to the atmosphere.

So remove moisture and keep a constant temp and you can store organic compounds for thousands of years (mummies) so given that a car is a piece of cake.

In a normal garage without humidity control and a non heated area, I would absolutely start my car and allow it to come to temperature every two weeks.

Call me crazy.