Went to order some Oko plus at Zoopus (who I generally find are cheapest for it - even when at full price) and the 40L sack is on offer at £19.99 instead of £24.99. Delivery is free over £19 but I wouldn't recommend adding anything else to the order as the 40L sacks weigh a ton so any tins or sachets are likely to be severly squished in Zooplus style common sense free packinging
http://www.zooplus.co.uk/shop/cats/cat_litter/biodegradable/bio_clumping/14001
