Cycle hire is cheap and the equipment will be of a high enough standard to make your day trouble free and enjoyable. Plus, many are situated next to purpose-built cycle routes networking across the countryside. The larger places are open all year round, but the schedule is slightly patchy from Nov. to March. If you want to hire then it is probably best to ring up and book so that you are guaranteed an open centre. For very small children There are usually trailers and buggies available for a few extra pounds.
Places cater for large parties such as school trips with enough notice.
Also, you'll need to leave a deposit depending on the number and type of bikes you take out, and the deposit can be large if there is a group of you, so it may be worth ringing to see whether you'll be needing that credit card. Don't forget safety gear as well. Just because you'll only be out for an hour, doesn't mean that you won't injure yourself. If you have your own, then take it, otherwise helmets are available and are usually free if you hire a bike.