Take your website and post it
The article said: "Customers have been struggling to access the service and some have been shuttered out of Parcelforce's website altogether, because Windows 7, Vista and Linux platforms "failed to meet the necessary requirements" to enable punters to make a transaction."
So basically what Parcelfarce are saying is "use Windows XP or Mac or go elsewhere" - fine in that case the 'go elsewhere' option looks attractive to me. Strangely enough, the RoyalMail website seems to work fine with Windows 7 and Linux (Ubuntu 8.04 in my case for the latter) - even the purchase postage online option works fine (used it yesterday).
To take the posting to a technical level - I'd be interested to hear what's so special about the IE+Vista or IE+Win7 combo that makes them fail but the _same version_ of IE and XP work. Oh, and when they say that (presumably) they support XP, is that XP+IE only or are Opera, FF, Chrome, etc supported?
I'd recommend that Parcelfarce fire their current eCommerce team, and get in some folks that have a better appreciation of how the service is supposed to work. Or is the online bit just a feature that the pointy-haired-bosses wanted, but everyone else didn't? Certainly the poor state of it (according to the article) seems to suggest a lack of technical commitment.