OS X 10.10.5 Update

[#1]

I am in the process of downloading this and it is taking way to long with the time remaining is going up and down like a yoyo. As I type I have 281MB of 815MB and so far I've been told this will be complete in 1h 40m or maybe 59m, oh now its 1h 57m.
Is / has anyone else experienced this?
Edit:
I am now at 338MB and I still have 1h 57m remaining! Surely there must be something wrong? I can appreciate the network may be busy with users updating but considering my very limited download speed I would expect it to at least be constant, like it is everywhere else I download from.

[#2]

you could be connected to a bad CDN.

[#3]

It certainly looked like it, it took way longer that it should have to download, but it's done now. Having said that I've since seen references on TBB questioning Plusnet's capacity on this.