The pair of 10MHz is split for uplink and downlink and the 5MHz is for “downlink only”, presumably for the same reasons that domestic broadband is asymmetric.
The three most important words in any estate agent's lexicon are: "Location, location, location." The same is true for the UK's mobile carriers, who have just spent £23m to get their choice positions for their recent spectrum purchases. Dubbed the "assignment phase," this comparatively modest spendathon has followed Ofcom's …
Or you could read the article and see they spent over a billion just on getting this far before this auction - and that's when they are still allowed to keep/reuse their 3G/4G spectrum for the most part.
This is a billion-dollar industry, and the frequency allocations are critical to customer satisfaction in terms of coverage and speed. The company behind Three alone is worth 10's of billions of dollars just by itself, not counting what money actually goes through it in the average year and is spent on actually providing its service.
It costs £5m per kilometre of undersea cable, for instance, so there is far, far, far more expenditure in dropping a few fibres between countries than the entire telecoms spectrum.
They wouldn't be paying this money if they didn't think they'd be getting it back, or if they could skimp on it and still beat their competitors.
Article date: May 2000
.... raised £22.5 billion for the government from an auction of radio bandwidths for 3G mobile phone licenses.
£22.5 billion in 2000 = £39.40 billion in 2021!