In reply to nfn:
Given that the government site (as at today's date) says that two weeks quarantine is necessary upon arrival from the UK. Being in a van wouldn't make you exempt from that.
From gov.uk
""
Travel is subject to entry restrictions
UK nationals entering France from outside the European Area are required to certify that their journey to France is essential and complete relevant documentation
Arrivals from the UK and some other countries are asked to self-isolate for 14 days on arrival in mainland France"".
How is that possible in a van?