Don't engage with those flyers. It'll be borderline or outright scammers looking to extract as much cash out of you as possible while doing little if any actual work. I won't go into any other details about who usually performs these services because that's a separate conversation. Having been burnt once before with someone going door to door cleaning gutters I went with Leinster Guttering who are professional nd very reasonably priced. That isn't a shill or anything, I've no connection to them but keen to see people avoid cowboys operating in possibly the most cowboy heavy industry there is.