Missing stamp is not an issue just more hassle with journey logs and showing more papers, go enjoy your trip to Calais & L2K
No one clearly understands when a passport should be stamped at EU/UK borders but for sure they can't stamp ID cards, from Oct this applies only to those with Art50 privileges who can still use ID cards untill they die
https://eur-lex.europa.eu/legal-content ... 89&from=EN“Article 11 of the SBC introduces a possible presumption of illegal stay of a third-country national found on the territory of a Schengen Member State or when exiting the Schengen area without bearing an entry stamp. In this situation, the third-country national may rebut the presumption by providing, by any means, credible evidence, such as transport tickets or hotel bills, proof of his/her presence outside the Schengen area, that he/she has respected the condition of a short stay in the Schengen zone. In such a case, the competent national authorities shall indicate in the travel document, in accordance with national law and practice, the date and the place of the crossing of the external border of one of the Member States.”