ALD advise that you will need to get in touch with them at least 28 days before your trip so that they can send the VE103 out to you before you travel. You will need to contact their Driver Assistance Team on 08000323277 to arrange this.
They also advise that it will be your responsibility to familiarise yourself with any driving laws and regulations in the country you are visiting.
You will need to make sure that your insurance covers you whilst travelling, and you should carry a copy of your vehicle insurance certificate with you.
ALD do offer AA Fleet Europe for an additional cost if you would like to take this out. This would cover you for mechanical breakdowns across Europe for a trip of up to 90 days. You can request more information on this when you call to request your VE103.