BBC iplayer/catch up question

I downloaded this on BBC catch up, intending to watch it in a couple of long sessions. Went to start it and episodes 1&2 were missing. Checked in iplayer and they are no longer available there. Does iplayer also delete them from the sky box when they expire?

On separate note, I ended up downloading them and it seems the series originally aired in november 2014 (presumably in the US?)