The article seems to imply that the carrier should have adopted US LTE frequencies.
The problem is, the North American LTE frequencies are quite different from the rest of the world. You have to expect that any NA-bound LTE devices wouldn't work on Europe or any other place.
Here's a basic rundown of the major frequencies in use:
North America: band 2 (1900MHz), band 4 (1700/2100MHz), bands 12/13/17 (700MHz)
Europe/Asia/etc.: band 3 (1800MHz), bands 5/20 (800MHz), band 7 (2.6GHz)
Because of this, even the current LTE chips with multiple frequency support has to choose between North American and European baseband firmware, necessitating separate models for NA and Europe release.
In terms of number of carriers behind each frequencies, 1.8GHz is the second most preferred after 2.6GHz. So I think it was sensible for the UK carrier to get behind it.
Personally, I'm waiting to see if there will be an LTE iPhone with non-US LTE frequency support. If this happens, device provision issue should lessen, as it is a popular phone - there will be a lot of demand and the competitors will release models with similar frequency support to prevent losing market share.