Listen Again at a glance
I think the "listen again" part of the website is great (apart from the restricted bandwidth on the audio). I think what would be even better is to present all the audio on a single page. You could have a timeline along the top, going from 12 am to 12 am and all the channels down the side. Each programme could be represented as divisions on the bars going across the page, similar to the listings pages at radiotimes.com.
What would be even better is if you could go backwards on the listings pages and just click on a programme title to hear the audio again, though I expect there may be a commercial/non-commercial clash here.