32 Mb & 29Mb seem to be quite low speeds for only 650m from the cabinet.
I am between 900m & 1000m from my cabinet & my estimate is 30Mb.
Actual sync speed is usually around that, sometimes a little higher.
The reason for low installation sync speed anyway could be that you are actually further than 650m from the cabinet (you may even be connected to a different cabinet).
Or it could be that your connection is all aluminium cabling.
Or it could be there is a "fault" on the line that wasn't detected by the installing engineer's basic tests.
The fact that your connection speed dropped & seems to have stuck at 15Mb suggests a connection that experiences very many errors/resyncs etc., thus causing DLM to set a low sync speed to try to ensure stability i.e. it MAY have something like a high resistance fault that doesn't completely disable broadband & internet..
The only realistic way to attempt to diagnose matters for yourself is to unlock the modem (Assuming it is the Huawei HG612 model) & have a look at its stats, particularly bit-loading, QLN, SNR, Hlog, Line & Signal attenuation.
If there is nothing obvious standing out from your current stats, if you are a Windows user, you could graph any changes in noise levels, error counts etc. by auto-logging your stats continuously over say a few days at a time.
That may highlight either general "issues" or issues that occur at the same time every day/night.
Someone with access to the post code checker may be able to confirm which cabinet you are actually connected to for you to check a realistic distance.
What is your exact IP Profile from the BT tester?
From that we could roughly calculate your sync speed.
If IP Profile just happens to be 14.52Mb, it would suggest a sync speed capped by DLM at 14999K (15Mb).
Does the connection ever drop when using the phone, either receiving or dialling a call?
Edited by Bald_Eagle1 (Wed 13-Jun-12 06:59:06)