I have for sale a set of Avenir cycle panniers which have been used once on short cycling holiday. Indeed, these were all I needed to fit in all my gear for a five day break to the Isle of Man. They would be great for commuting too.

I would estimate they hold around 40L if you include the attachable rucksack.

The link to the current ebay version is here (mine were purchased about 5 years ago) and they current retail for around £50:

http://www.ebay.co.uk/itm/2014-Avenir-Triple-pannier-deluxe-touring-commuter-bike-bag-40-litre-w-rucksack-/310844863889?pt=UK_SportGoods_CyclAcces_RL&hash=item485fcc3591

They are green/grey/black in colour and have numerous places for storage: 2 large side paniers, each with an outside pocket and 4 additional smaller side pockets. The rucksack is comfy and had 1 large main pocket and 3 outside zipped pockets of varying sizes. The rucksack attaches to the panniers via a zip with the straps being on the inside of the 'package'. The zips are all sturdy and working. There is reflective piping around everything and the paniers clip into place easily. The only slight defect is that one of the underneath straps has become frayed. This does not affect the use of the pannier, in fact, I don't think I even ever used this strap.

If you are local, you are welcome to collect from Waterbeach, 4 miles north of Cambridge.