981 Cayman Streaming Up overnight

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I live in the NE of Scotland and now winter is here and the resultant overnight cold temps I get up every morning to find my car all steamed (fogged) up inside, windscreen almost streaming its that bad.

I always have the A/C on, never too high temp either (20degC). Don't think its wet ie a leak

Anyone got similar experience and / or know of a fix?