The UK has a bad track record when it comes to keeping their TV series.
But some of those lost episodes were recorded on audio tape by viewers:
Here's a few of them on youtube, including Till Death Us Do part and Morecambe & Wise. (http://www.youtube.com/channel/UCUXYpm1y93TFBRyP_kN4xLQ/playlists)
I wonder if there are any more tapes (reels) like this out there...?