Have you taken a look at your passport recently?
If you are travelling abroad most countries will not accept you if the expiry date is less than six months. This does not apply to the Channel Islands or the Isle of Man for which no passport is required, nor for cruise ships on short ex-UK trips that do not visit foreign ports. However, if adults are taking children under 18 that do not belong to them (ie grandchildren) some form of authority is required.
The Passport Office has been putting out dire warnings that it might take up to 10 weeks to process an application, but reports indicate 2/3 weeks is more the norm.
If a standard application is made and paid for, but needs to be upgraded to fast track, a new fast track application will be required, and under certain conditions a refund of the original fee can be made. The Standard fee is £75, Fast Track £142 (seven days) and the 24hr Premium Service £177. At present a passport has a life of 10 years, but there is every indication they will be replaced with an app.