Flies!

AlanDrover

Can anyone suggest a product or method of stopping flies from congregating to hibernate in the small gap along the top of caravan windows, please? Having owned caravans of different types for many years, I know this is a regular autumn problem, but this
year, it seems to be particularly bad! I cleared them all out, only to find, just quarter of an hour later, many of them had resumed their comfy positions!

Any suggestions welcomed!

Thanks!

Alan