I was watching an old episode of Have I Got News For You and a David Cameron promotional site was mentioned so I checked it out. His people must have let the domain name expire as it’s now a spam blog called David Cameron Journalism.
David Cameron improving your life, one shitty link farm at a time.
The campaign website belongs to the person - or political party - running it. They aren’t official government websites, so they aren’t eligible to be automatically archived at https://www.nationalarchives.gov.uk/webarchive/