In reply to tcashmore:
Arrived in France last Thursday via eurotunnel.. Never used the tunnel before and fully expected a cheery welcome from French passport control and the customs raiding any food we had.
Turns out you drive off the train and get straight on the autoroute passing through no checks at all, those having all been done uk side. Checks UK side only entailed two brief glances at UK passport control and French Passport control mind you, no vehicle checks or anything else.
We haven't been asked for anything covid or passport related since we left the French passport kiosk in the UK Eurotunnel terminal.
Mask wearing in shops etc seems to be 100 percent. The one and only lift queue last Saturday morning was a mixutre of masks, buffs or nothing.
I think your declaration / sworn statement is simply them getting it in writing that you agree to a lat flow (antigen test) if they challenge you. From what we have seen the chances are very low indeed.
Have a good trip!
Post edited at 17:40