Simon's Bike Trips - Things To Take

Tools - make sure you have enough tools for simple maintenance e.g. chain adjustment. Don't double up if two of you have the same bike, take half each. A small socket set with allen keys and a pair of pliers can prove invaluable.
Spare headlight, tail light and indicator bulbs. This is a legal requirement in some countries but makes sense anyway.
Fixing a puncture at the side of the road is no fun. Make sure at least one of you takes a can of Finelec or something similar to get you to somewhere where you can get a proper repair done or get a new tyre.
Money. Take some Euros and a Visa or Mastercard. Use the cash for boozing and use the credit card for petrol, hotels and motorway tolls. Credit cards usually give a better exchange rate than a high street bank or Thomas Cook, but make sure you've budgeted for the bill when it arrives, after you get back home.
Insurance - make sure you have adequate cover for all the countries you might visit. Take an E111 and get breakdown as well as personal travel insurance. For breakdown cover, AA 5 Star Europe or RAC European Cover is well worth the money. If you go abroad more than once a year you'll probably find that an annual personal travel insurance policy will save money in the long run (if you get a family policy, make sure it still covers you when you travel on your own).