New Fibre Installation

[#1]

Plusnet Fibre is probably as reliable as any other DSL based technology.  The good news is you appear to be achieving maximum sync speed with the cabinet, the bad news is that something between there an the internet is 'killing' what should be a fantastic connection.  The TAP3 test would be pretty helpful as it shown if the problem is likely to be in the ISP side of things or somewhere else (exchange for example) but, like you, I've had difficulty with this test on the occasions I've wanted to use it.
Once your problem is identified it should be fixed then you can look forward to really good internet.  I'd say let Plusnet Faults sort this out but do keep on at them until it's fixed if necesary.

[#2]

Well still no broadband since changing to fibre on the 20th June!
Asked to go back to my old package and just get quoted 'you are in contract now for fibre' my reply 'but I haven't even got an internet connection'
Then told to basically check my TC........ Oh, plusnet still want paying of course! 

[#3]

@notveryhappy
Sorry to hear that this isn't resolved for you yet. We're chasing this today and our faults team will update you ASAP.
Any downtime that you incur we'll more than happy look at a goodwill gesture for this once your services are up and running.