I really hope for you that you do not do this for a living. The UK, specially the UK, where until now every second iPad and other Apple stuff (ex iPhone) is brought in directly from the states, the UK, that has the highest quota of regular business and private travel between the two countries, the UK is going to be the last complaining about a product that allows them finally to roam on both continents with speed.
What in your opinion would have been gained to install a LTE chip that will support the non existing british networks (that the frequencies and bands are not even known until next year seems to be a meer technicallity as well) that will not work in britons favorite travel destination?
Fact remains, the new iPad IS supporting LTE 4G. It is NOT supporting it in the UK but then, no device is, because IT DOES NOT EXIST.
I haven't for a moment suggested that they should have included an 800/2600MHz LTE Chip. In fact, I've argued that it wouldn't make sense to sell a separate model in the EU due to the immature nature of most EU Member State's 4G Deployments. What we do know is that UK Networks (with the possible exception of "Everything Everywhere") will follow the EU Guideline to allocate 800/2600MHz as the Standard LTE Spectrum. Trials are happening and the Licenses will be purchased at auction sometime after Analogue Television signals finally die in April with initial LTE Deployments being switched-on before the end of this year and yet still...I don't care one bit whether Apple supports these standards.
What I do care about is being lied to. A device that cannot support 4G outside of America is not 4G to any non-American and should not be sold as such. At best it's misleading, at worst disingenuous, and local law (meaning EU Law) supports the consumer in this regard. The device should be sold without "4G" being thrust to the forefront in available descriptions.
In the 80s/90s, A "Foreign" (to the US) Manufacturer wouldn't have sold an American a Television claiming it had the "Feature" of Higher Resolution than any other television sold in the US on the off-chance that they might lug that television to another country and take advantage of PAL Broadcasts.
European cars sold in America tend to be poor cousins of their European counterparts, simply because Europe standardises on much higher Octane fuel (typically "Premium"/"Super Unleaded" (97 RON) is the LOWEST rated fuel with 95 RON being the EU Legal Minimum). We insist that for use in the US, users utilise only the highest Octane fuels OR convert the cars (or manufacture them especially) to accept the "dirtier" fuels in North America/Australasia. What the likes of VW & BMW don't then do in their marketing for converted cars is quote the EU Figures for Acceleration and BHP etc. because these would be outright lies as any Turbochargers simply wouldn't work as well with US gas.
It's just common sense, a Product should not have a feature so pre-eminently championed in it's marketing that is so severely tied to being in another geographical region outside your own.
PS. The vast majority of travel by UK Nationals is to EU Member States where we have freedom of movement across borders to live & work. I don't know where you obtained your data, but it probably has something to do with London Heathrow Airport acting as something of a Hub Airport into Europe for flights of Trans-Atlantic Origin.
I also severely doubt that 1 in 2 iPads sold in the UK ship from the US. The benefits of a favourable exchange rate are obliterated by the Sales/Import taxes involved, the additional power converter purchase required to utilise 230/240V Electrical Sockets, and the inconvenience of the time taken to make the delivery. We're certainly characteristically a frugal culture, but we're not THAT cheap!