The original route started up an easy chimney and then traversed out to a poor bolt and a peg and continued up the arete with shitty protection. This meant you needed to step into Quo Vadis to find protection and avoided the arete at this point. The route then stepped back onto the arete which it followed for a while with no further worthwhile protection. The easiest finish (given the lack of protection) was up the wall left of the arete.
A short while later Mike Law came back and added the bouldery Direct Start (21) which had no worthwhile protection.
My experience with the route was about twenty years ago when I led it (minus the direct start). I thought the climb was very flawed. The pro was seriously crap (including the fixed gear) and the route wandered around avoiding some of the best bits of the arete. I have also never heard of anyone repeating the direct start.
I had always wanted to go back and check out Jenny Wren and see if it could be improved. Unfortunately I never got around to it. Whilst working on the second edition of the Araps guide I simply wrote a vague description along the lines of '...a variety of fixed gear (most of which has been replaced)'. I figured I would re-equip the route once the guidebook went to the printers.
Unfortunately I got sidetracked (probably something to do with renovating a cafe) and Jenny Wren remained in its original state after the guidebook was published. I then heard about a climber leading it and having a rather terrifying experience as a result of the protection on offer. I then had an attack of the guilts and recruited another local to come with me and suss things out properly.
After top-roping the route we then placed two bolts in the direct start, another three bolts in the arete and rap-anchor at the top. The original bolt and peg are still there (with a new bolt between them).
The end result is a vastly improved route. Despite the extra bolts, the climb still feels pretty run-out. The Direct Start is now the standard start (and is considered solid grade 21). The step into Quo Vadis is eliminated and the climb remains on the very arete with some more exciting moves at grade 20. The climb then finishes directly up the final part of the arete (instead of escaping up the left wall) with moderate but spectacular climbing above the last bolt.
The chain at the top allows you to rap back down to Blockbuster Ledge and is easily accessible from any of the other climbs that finish at the top of the Bluffs. A 25m rap will land you at some very easy scrambling just a metre or two above Blockbuster Ledge and is great if you want to also climb Quo Vadis, Scorpion etc.
Jenny Wren (21) is arguably a two-star route now. It follows the arete all the way and still has that run-out element to keep you on your toes.