Line speed dropping significantly

[#1]

So I've been away for a while and on my return my line speed seems to have dropped significantly.  When I left in December it was hovering around the 70Mbps mark down and around 14 Mbps up IIRC.  Now I've dropped right down to 48.8Mbps / 10.88Mbps.  IP Profile is now 50.93.  Any reason for this drop?
Should add I updated my router firmware today, which necessitated resetting a couple of times.  Will this have made a difference?

[#2]

Is no-one from Support on today?

[#3]

Looks like the line is in sync slightly below the estimates for your line.
Sync: 52.6 Mbps down/12.8 Mbps up.
Estimates: 53.1 Mbps - 68.8 Mbps down/13.3 Mbps - 19.8 Mbps up.
Might be worth raising it at http://faults.plus.net for further investigation.

[#4]

Ok thanks.  Just have done.
My connection has always been around 68Mbps or so.  Don't understand why it's dropped so much

[#5]

No reply from Support, so I'm guessing this won't get picked up until Tuesday now

[#6]

So today I get the following reply from Support:
Dear Mr xxx,
Thanks for your patience. From testing your circuit, I can see that your issue is resolved as the connection is remaining stable and the speed looks great. Please continue to monitor and get back in touch if you have any further problems.
Please do not hesitate to get back in touch online at http://contactus.plus.net or by phone on 0800 432 0200 or 0345 140 0200 if we can be of further assistance.
I don't know how they define "looks great" over there but today I did a BT test and my speed has dropped to 39.7Mbps, a further 10Mbps from just a couple of days ago and almost half of what I was enjoying just a few months ago.  Can someone please investigate this properly as this response doesn't even address the issue I had?
1. Best Effort Test:  -provides background information.
Download Speed
39.7 Mbps

0 Mbps 50.93 Mbps
Max Achievable Speed
Download speedachieved during the test was - 39.7 Mbps
For your connection, the acceptable range of speedsis 35.65 Mbps-50.93 Mbps .
Additional Information:
IP Profile for your line is - 50.93 Mbps
2. Upstream Test:  -provides background information.
Upload Speed
10.29 Mbps

0 Mbps 20 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 10.29Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps

[#7]

Hi.
What is the equipment you are using? Modem/ router model?
Was the connection switched off while you were away? Or left on?
How are you speed testing : wired or wireless?
Could be that your account renewed while you were away, old contract ended , and your new one has not been reinstated on the same terms?
I'd get on the phone and enquire if were you!
Good luck!

[#8]

Modem is the OR one installed when I took the package.  Router is Asus RT-N66u.  Stability is not an issue, but speed definitely is as my IP profile has dropped by nearly 30% and my speed even further than that.  My contract is not up for renewal and nothing has changed.  I've been away for work but my family has continued to use the connection.  Such a massive drop deserves more than simply "everything looks great" IMO.

[#9]

I would agree with you, a 50% fall is not realistic . Call support and see if your package has been changed or if your profile has altered in error. Mine slipped about 3 months into my fibre contract. It went from 10Mb/s to 2Mbs for no apparent reason. A quick call to support was all it took to fix it - and they could not give me any reason why it changed, but it had and it was fixed in an instant.

[#10]

Shure, you still haven't confirmed if you are using wired or wireless.

[#11]

Apologies.  Wired every time.  But it's also the fact that my IP Profile has dropped so much

[#12]

DLM would have altered the IP Profile, if line is OK then maybe you'll have to wait for DLM to restore speed?
This could take days to weeks (providing line is stable)