It says pretty plainly that it will not be using XP for the operational systems, what can I say?
By the time the US rolls the first Type 26 off the production line, the type 26 will already be in operational service will have ironed out the bugs and can apply any lessons learned to the US ships. Much of the equipment used on the Type 26 is already in operational service elsewhere anyway, including generators produced by General Electric that are also in service with the US Navy in the Zumwalt class and the MT30 gas turbine already in service with the Zumwalt class, Freedom Class and the QE class.
Some of the tech will be new and untested of course, but unless you want your ships to be obsolte before they’re even completed, you have to push the envelope and try untested tech that will need to be debugged during operational service, which the Royal Navy will be doing anyway before the first US frigate hits the water. There is however, nothing to match the hull design which will be the most accoustically quiet in the world and optimised for anti-sub warfare, which is perhaps the most dangerous threat to the USN because they can actually get close enough to pose a threat, unlike enemy surface combatants. Other designs are more general purpose frigates that are not optimised to anywhere the same extent for ASW as the Type 26.
The specialization of the Type 26 may be a problem - these are supposed to be anti-air specialist frigates with ASW a distinct and distant second.
The problem with your assertion that ‘by the time you build one the production U.K. one will have been in service and had the bugs fixed - how long has the Type 45 been in service? And it still doesn’t have the power plant problems fixed?