I have used a standard ( ie not made to measure) cover for years on my third or fourth now just a maypole or similar make as we are infrequent caravan users and the cover helps to keep the caravan clean? I never had any problems with damage to the caravan etc but I do have a 14 yr old caravan ? I also tow with a front cover , I had a stone damage the front window on our previous caravan so thought I try one again not made to measure I’ve used this cover 3 or four time it’s been fine and agin helps keep the caravan front clean when towing.