How long does a new line take to settle down?

[#1]

ADSL on my new line was activated on Sunday morning, and it's now almost  7 days later (Friday PM) but still have an unusable connection..
Despite having a connection capable of streaming in iPlayer HD, it constantly buffers even in 'low quality' mode. YouTube pages either take a good minute to buffer, or don't load at all. Other websites constantly bring up the 'The page can't be found' error, but usually load ok after refreshing a few times.
I'm using the same router and same computer as I did in my old house, with no changes to either.
As suggested somewhere on the PN website, I have rebooted the router each morning at 7am before leaving for work, which apparently helps (?)
Is this something wrong at my end, the new line still getting it's feet on steady ground... or is there something wrong with BT/PN at the moment?
Any advice or suggestions appreciated !!
Speedtest result on Monday was:

Speedtest now (Friday):

(Slower, but I'm perfectly happy with it if I could actually use it!)

Router stats (Friday):
Current DSL Connection:
Current DSL Connection:
                Down         Up
Rate:         7616 kbs    448 kbs
Max Rate: 8812 kbs       1016 kbs
Noise Margin: 13.0 dB       24.0 dB
Attenuation: 20.7 dB       12.0 dB
Output Power: 19.8 dBm      12.1 dBm
Protocol: G.DMT Annex A
Channel: Interleaved
DSLAM Vendor Information Country: {46336} Vendor: {TSTC} Specific: {0 }
ATM PVC: 0/38
Rate Cap: 8812 kbs
Attenuation @ 300kHz:                 20.7 dB
Uncanceled Echo:           -17.1 dB Ok
VCXO Frequency Offset: -9.7 ppm Ok
Final Receive Gain:         4.5 dB Ok
Impulse Noise Comp. Tones:    0 Ok
Excessive Impulse Noise:     0 Ok

[#2]

10 days

[#3]

7.38Mb/s on ADSL (up to 8Meg) ? With that line sync speed of 7616k would limit your line speed of no more than 6.50Mb/s due to BT's ip profile cap at 6500K. That's odd speed. Yes, it take the first 10 days to settle down.

[#4]

When testing speeds with speed net try and use the same server
your first result was manchester with a distance of 150 miles the second was milton keynes with a distance of less than 50

[#5]

I've been working away this weekend and due to return home tomorrow morning, which will be 11 days since activation.
I'm pretty sure the sync speed lowered after the first day. I was surprised that it was over 7 too, as I was told it should be between 5 and 6.5. Perhaps a small glitch on speedtest.net when I used it.
Just managed to use remote desktop (via logmein.com) and it was a good stable coonnection, so looks good even from 200 miles away!

[#6]

11 days after activation and I'm now getting a rock solid 6.3Mb
iPlayer and Youtube seem to be working fine again, so my earlier problems were down to the line settling or a temporary glitch on PN