Your bill might affect the interests of the King or royal family, and would therefore need consent from the King or the Prince of Wales. The Public Bill Office will tell you if your bill needs this.
The Joint Committee on Human Rights may also contact you, if they think that your bill may be incompatible with the Human Rights Act 1998.
The Clerk of Private Members’ Bills will be able to advise you whether any of these things is likely to happen once you submit your draft bill.