I have been looking for these for ages, and kept coming up with a site that seemed to want best part of £50 to connect my 2 ibc tanks together so I made my own temp fittings.
Just found this place selling them on ebay
http://stores.shop.ebay.co.uk/regenwassertanks-wn64__W0QQ_armrsZ1They are less than half the price of the other places I looked and less than half the price on delivery also
Hope this helps some people on here.
Ian