New fibre line, after 4 days, slower than adsl

[#1]

Hi all.
I'm wondering if I should be waiting for an improvement or if I should see this
as a potential fault.
From Plusnet,
Estimated line speed:
   27Mb (This may vary between 18Mb and 27.1Mb) - Checked on 2016-01-31 16:55:27
Current line speed:
   12.6 Mb
Went live on the 23rd.
It was 27Mb for a while on the 1st day, went to 25 , then 14, and now 12.6
The line dropped twice, that I noticed, on the 1st night.
My adsl line was a solid 17.9 from day one on adsl 2+
Update:
I've just found a link to the btwholesale speedtester, and using my laptop via ethernet,
it told me there is no fibre on my line.
I tried again, this time choosing the adsl test, and got some results,
"Download speed achieved during the test was 12.1Mbps.
For your connection, the acceptable range of speeds is 20Mbps to 12.67Mbps(sic).
Additional Information:
IP Profile for your line is 12.67Mbps.
Upstream speed was 1.8Mbps,
Upstream rate IP Profile is 2.0Mbps.
Am I or am I not using fibre?
Any help would be appreciated.

[#2]

The max upload speed on ADSL is 1Mbps. Given your upstream IP Profile you appear to be on the 40/2 Fibre product.
There is no training period for Fibre so I would be looking at reporting a potential fault.

[#3]

Thanks for confirming what I suspected.
I'll get onto it.
adie:quote