there's an outage which means CF is off where I am.
So I've failedover to the Virgin circuit....
I'm sure it's no coincidence but as CF are very close to available in my area (fibre now being blown to poles) Virgin have started offering everyone the new DOCSIS 3.1 capable Hub 4. It's early days but the additional downstream bandwidth seems to have sorted a lot out.
On another note, I wonder how many people now consider a backup internet connection a necessity. An FTTC circuit can be had for less than £20 ex VAT per month, which is far lower than the cost difference between any of the consumer FTTP/DOCSIS packages and a leased line with proper SLA.