If Jago have gone to the BBC with the design that they came up with, why shouldn't they also supply the same elements to other broadcasters? The success and look of the BBC designs will be a big part of why broadcasters on the opposite side of the world are using them to design their sets.
Well, let's say you own a company and you pay some designer to come up with its logo. Would you be happy if the designer of that "distinctive" logo then goes and sells a lookalike logo to another company? Your logo would suddenly cease to be unique.
In that case though you own the rights to the design. If the BBC contracted Jago for an exclusive design, we can be sure the elements wouldn't appear elsewhere, simply because the BBC are still happy to work with Jago and have their sets as part of Jago's portfolio.
Just look at website designs. There's plenty of design companies who every website they sell is an alteration of a template they designed. And they suck up customers who only want a website that looks like that one they saw.
True, that happens a lot in the U.S., where stations buy sets, graphics, and music on a market-exclusive basis. For instance, the same news theme may be heard on unrelated stations in Chicago, Atlanta, and San Francisco.
The BBC is different, however, because BBC World News is distributed globally. If Jago Design begins to sell the same design to other broadcasters around the world, viewers will notice its similarity to the BBC's look. That's why I assumed, perhaps wrongly, that the BBC paid Jago for an exclusive design.