He changed his trousers JMO. I commented earlier that his light coloured trousers looked clean at the service station at 2am ish. Looking at the video cam of him talking to SE near the car before kidnapping her, I think he was wearing different trousers. You can't tell colour from these cctv things well, but the earlier ones looked darker and a different shape.
Killer cop Wayne Couzens's wife Olena 'silently watched him face justice' | Daily Mail Online
He didn't change his clothes
The court heard how the morning after murdering Sarah, Mr Couzens went into a Costa Coffee in Biggin Street, Dover, where he bought a hot chocolate with coconut milk and a Bakewell Tart, while still wearing the same clothing as the previous evening.
Wayne Couzens took kids to woods where he left Sarah Everard's burned body