Under the ri/epost I have an R from serrs (Blunder between left and right hands of salutes forces men closer together) so I think the answer should be 6 letters R?POST. But, knowing me, I'm wrong
Ripper, I wasn't as smart as Roslyn - I went with Repos(t) as Repos is a word (the grid meant we needed a 5-letter answer, a real word) and Ripos isn't!