I'm about to lose my storage for my 90 that lives in north wales. What's the verdict on storing vehicles outside that aren't used much. Should I buy a good tarp to cover it and keep the weather off or is this likely to do more harm than good with the landy sweating and rotting under the sheet??

Cover it but first of all put a cotton dust sheet or blanket over it to stop the tarp from scratching the paint work. and also cover any sharp edges & corners with some foam rubber or similar to stop them from tearing the tarp.

The wind blowing under the vehicle will prevent any damp/condensation buildup.