i think archie must have found it.
when billy cried for help and roxy shoved it in between the boxes, archie must of seen her from the top of the stairs or something and then later blackmailed suzy and then told her to expose the secret.
How pathetic was the whole thing tho! So Archie got the results, gave them to stupid Suzie, and then changed his mind and wanted them back after paying her �10 grand to tell everyone! And it took Sean like 5 minutes to work out who the real dad was!
And Roxy was stupid to leave it lying about, any normal person would have burnt it straight away.
I also remember the letter being given to Roxy (by Peggy, I think?) after Ben had supposedly found it....unless it was Archie who found it, put it back when Ben could have lifted it and handed it to Peggy, who in turn passed it back to Roxy.
If Archie did take a copy, we certainly didn't see it. Maybe the photocopier is in the same room in the Vic where the pub food is cooked!