thanks guys. It would seem the answer to 3dn is Extranet (new one on me - but I've googled it and it seems to fit the clue) and 12ac is indeed Sheba. Posted this in case anyone else gets stuck.
An extranet is, essentially, a combination of an intranet and an Internet site. E.g. if you consider the Amazon website, the general public can buy things from it, but Amazon employees use an intranet application which they use to maintain the product catalogue, do the back-office processing etc...