I get through about one pack of 24 diapers per month so it is important to find the most competative prices around. Being in the U.K. I have found this company
Value Incontinence - Full range of quality, branded incontinence products at low prices
You will need to ckick the unisex incontinence link and then the disposable all in ones to get to the tena slips.
to be the most competitive so far, I know I should have bought 4 packs and had the free post option but I am stupid and I ordered only three packs. I will know next time.
I hope this helps someone.
If you know somewhere cheaper to buy the same product and the same quantity how about posting a link here ?