When I say condensation, I mean on the large metal parts of the car like the engine and wheels. You'll get that in any detached well ventilated (unheated) garage if the outside air warms up a bit after a cold spell. Those parts of the car stay cold and the increased water content in the warmer air entering the garage condenses on them. A small tubular heater under the car will raise the temperature just enough for that not to happen. As I said, it's a cheap and simple solution. If you want to spend more the next level up is a Carcoon to control the humidity, and beyond that is a heated, insulated garage. Personally I think Carcoons are ugly and take up a lot of space in the garage. A heated, insulated garage would be lovely, but would cost £££.