In reply to john morrissey:
When we did mousetrap there was another party's rope in place. It was a 50 or 60 with another rope tied on. I remember thinking that when I passed the knot, which was at the top of quite an awkward step, that I was glad I was abseiling it.
What I would say is that the abseil is on ground which makes it easy for a knot to be passed so I would recommend this approach rather than an uncertain down climb.
It is well worth it anyway.
Andy