Ok.... I cancelled my pre-order last night after the online chat.
I then went to try to re-place an order to be delivered to my mum and dad's address (as that's where I am the week after). But because I'd ordered via the student store it wouldn't let me as it said I'd already ordered one (cancellation hadn't come through at that point., also there was only one type cover available (purple).
So I called again this morning from the number listed on the UK store website, the lady there said the exact same thing the lady said the first time I called back in June... that if it's pre-ordered it will be delivered ON the 28. I asked if I pre-ordered again today whether that would still count, she went away to check somewhere and came backs saying Yes, if the item is in stock it will be delivered on or by 28th.
I then got her to check stocks, there was still stock available of the i7 256, but the blue type cover (mid blue - probably like the best buy USA colour) was not available, only the purple, as I'd seen on the store last night.
So I then ordered the i7 and the purple cover again over the phone and got them delivered to my work address - taking a chance that she was correct.
On the help page of the UK store it says that items on pre-order will be delivered IMMEDIATELY, which is odd wording if 5-7 days after the release date.... so I'm taking the chance.. but I could be disappointed.
I guess I wait and see if I get a shipping confirmation before 28th... I wish I hadn't cancelled now as I'm in the same position I was before!
It seems information provided is not consistent.