I'd assumed they changed into "going away" gear at the wedding reception, but whatever Harriet is wearing, it's warm enough that she doesn't want to change for dinner when they finally get into Talboys. What with the furs and the eiderdown they are probably fairly closely coccooned, which makes enthusiastic snogging (but nothing requiring actual movement) more likely than being able to disentangle themselves silently at short notice.

Given that Peter goes to huge effort to clear out the shed for the car because he's worried about the weather, I was relieved that you didn't inflict rain on them again.