Amazon Cloud Drive from the UK is fast enough to not be a bottleneck (in comparison to Backblaze, which seemed to be limited somewhere between the UK and the US).
Backblaze did launch a speedtest site recently, may be useful for others considering using their services.
https://www.backblaze.com/speedtest/Personally been happy with them so far to keep 2 computers backed up, but not sure what I'll go with long term. I'm still debating if I need to back up my NAS data based on most of it being my media archive. I question if it's worth the cost vs rereipping in a loss, vs not even caring about having local media with current online offerings.