This is normally acceptable as long as some preconditions are met. These include no money changing hands except for fuel costs. Should you consider providing this as a paying service you will need hire and reward insurance. 

Horseboxes like campervan are often only used a few timers per year and spend most of their time parked safely in a garage. If this mirrors your situation then you should look into a policy based on miles per year also known as a limited mileage policy.

If your friend holds the correct licence and is covered under your insurance policy then they may drive. Typical policies may state any driver over 25 or you may have named the additional driver or drivers explicitly in the policy.

Please refer to gov.uk driving abroad for the original statement All UK vehicle insurance provides the minimum third party cover to drive in other EU countries. The key takeaway is that your cover can be limited to third party only, please contact your broker to clarify the specific details on your individual policy for example green card inclusion. Also check that you have horsebox breakdown cover for travel into Europe.

Most brokers will provide a quotation based on the information given. If your vehicle exceeds the norm in weight or height please make your broker aware. 

Comprehensive insurance policies will normally cover damage caused by the stock being transferred.

Breakdown cover is optional, if your travel long distances this may be worth considering, if you drive locally then it may be cheaper to come to some arrangement with a local breakdown company or garage that provides this service.  For horsebox insurance please click here.

This is normally an extra that can be added to your policy either at purchase time or later if the need arises for this type of cover.

For vehicles between 3.5 to 7.5 tonnes, a C1 category license is required to drive.