EDIT: I'm going to wait before replying, too many posts at once! Igantius - about the AppleCare uplift, what the HE store gives, that isn't full AppleCare (because of the phonecalls) so I couldn't sell this on eBay at some point and say it has 3 year of AppleCare (with however much left)?
The HE Store used to call the three-year warranty something like a 'limited three-years parts and labour warranty' and when you were on the purchase page online, the option to get full AppleCare was describe as an 'uplift'.
It's now called an 'AppleCare Base Warranty Certificate for the Higher Education National Contract' and on the purchase pages on the online HE Store, there's an option to add AppleCare for the reduced rate - if you hadn't read the HE T&C's, you wouldn't know that you get a three-year warranty as standard. Which personally, I think is a wee bit sneaky!
As I've said above, the advantage of the uplift AppleCare was free postage if you need to send it back and global coverage - and, as the others have pointed out, free telephone support. I assume this is still the case, but can't guarantee it is.
But for, sake of argument, if the only difference was the telephone support, personally I think it would be misleading to describe this as AppleCare if you were trying to sell it - because the regular AppleCare has this, but the non-uplift HE one doesn't. (And if there are other differences, then even more so).
However, you could just put 'x amount of warranty remaining' - this, I suspect, is what most people care about! Whatever the type of warranty, it is transferrable, so no worries there!
I'm going to be buying a desktop from the HE Store and thought about doing the AC uplift - not because I need it, but because it make be more attractive to would-be purchasers if I was able to put that there was AppleCare. At the moment, I'm leaning more to not buying it as I think the standard three-year parts and labour warranty will be attractive enough. That said, if it was a laptop I was getting, the global coverage might be nice for a purchaser intending to travel.... However, the more I think about it, although I think the full AC would be more attractive to some buyers, I'm not convinced that one would necessarily recoup the cost of the uplift when selling it on.
Hope I didn't muddy the water too much - as I say, it was something I've been thinking about myself!
You'll have to ask someone who knows more about the HE scheme (I'm FE remember, FE <> HE) but I get the impression from people I've spoke to that you have to do it through the online store. I could very well be wrong on that so I'd suggest speaking to Apple or possibly the people who admin the scheme in your campus IT team.
Either online or via the HE Store telephone number will do the trick - from previous threads, people who have bought instore and managed to get the HE discount said they had the standard one-year warranty.
I rather suspect that the HE discount is only officially meant to be online or by phone, but it's at the store's discretion to match the price - if this is the case then this would explain why you don't get the three-year warranty (although as people seem to be able to get AppleCare at the reduced price, this is less of an issue).
This pet theory of mine would explain why some people haven't been able to get the HE price instore and were just offered the standard FE price.