Go Campers
The terms, clause 24 state a mandatory €10.50 charge per rental day regardless of route or insurance. That is €73.50 for seven rental days or €105 for ten; check whether it is already included in the quote.
The Basic insurance description states €3,500 body-damage liability. Confirm gravel cover and the water and chassis exclusions in the selected policy; do not assume they share the body-damage limit. An excess is possible liability after damage, not a routine rental fee.