Hi-Viz clothing.
Not yet a legal requirement in France but wear it anyway, especially in bad visibility or at night. Advised to have available to wear at road-side breakdowns (mandatory for car drivers).

UK Global European Health Insurance Card (European Health Insurance Card – previously E111)
UK medical cover when travelling in EU countries. EHIC is no longer available to UK citizens – replaced by UK Global Health Insurance Card (GHIC).  Apply through NHS website.

Ferry / Train Ticket
Otherwise you’ve wasted your time sorting out the above!

Ear Plugs
Riding higher speeds (especially on faster continental roads) without earplugs will damage your hearing, but the fatigue from excessive noise may damage your life expectancy!

Credit Card
Not just for fuel, but those on the spot speeding fines. (Worth carrying with you)

First Aid Kit
Optional, Plasters, bandage, antiseptic cream, any medication you require and….the best hangover cure you know.

Personal Insurance
It’s up to you if you want to take out private travel insurance e.g. Boots Travel Insurance etc

Phrase book
Optional. I just point and look stupid. Seems to work.