By Natalie Crookham Prince Harry’s tell-all memoir Spare is due to be published in the UK on Tuesday, January 10, but leaked excerpts have already provided some allegations against the Royal Family. The Firm has not spoken out about the claims and has remained silent since the release of Harry & Meghan on Netflix last month. Their response, or lack of, has been backed by 78 percent of Express.co.uk readers in a new poll. Kensington and Buckingham Palace have refused to comment on anything contained in Harry’s book, which is in keeping with their maxim of “never complain, never explain” and not…