@Dray lots of businesses need >330 Mbps. In fact lots of businesses are buying 10 Gbps and cursing it and thinking about using multiple 10 Gbps pipes.
Point of order:
Some of the biggest IT companies in the world don't come close to 10Gb even at their largest enterprise sites.
I'm unsure how many companies need to shift uncompressed UHD around. That's a pretty specialised requirement.
I've not seen many companies that generate so much data that they need to shift more than a 1Gb circuit can handle overnight but actually have an 'overnight' window to replicate data in. Replicating at that rate to a DR site causes issues of its own in terms of saturating a 1Gb link due to latency, BDP, loss, etc, let alone trying to saturate 10Gb.
The company you are talking about in Cornwall were trialling XGPON for BT; their enterprise requirements didn't justify 1Gb let alone 10Gb had they been paying full price.
The only companies I know that are buying 10Gb and need multiples are data centre providers and a very few enormous companies that handle massive amounts of data and run their own data centres. People like Google, Salesforce, etc, are these guys however there aren't many of them for obvious reasons. By the time you get to that kind of scale you start looking at leasing your own dark fibre and lighting wavelengths as you need them rather than buying 10Gb at a time.
Having worked with enterprise networks across a variety of companies of all sizes for the past 7 years and working for ISPs before that I think I have seen 10, perhaps 20 companies at most that have a link greater than 1Gb in size.