Advice needed

[Delboy]

During last week sometime the wife had been at the gym with the car.

At somepoint the car has been coated in something from the building site next door to the gym car park.

She only discovered this on Tuesday after washing the car and feeling the sandpaper like texture on the car.

She doesn't know if it's paint or something else.

She has since heard of at least one other car with the same problem although I suspect there will be others.

How should I sort this out?

Do we claim from our insurance or pursue Lidl who own the site?

Look forward to your thoughts.