Fibre speed dropped 7meg since installation

[#1]

Guyz
can some one please offer some advice, when i had fibre installed 7 weeks ago, I was getting a very good 34-35 meg, now its dropped off to 28, Ive done the speed test and its telling me my line is set to an IP profile of 29.4 meg. where has this come from, as when it was on at 35 meg it was very very stable, i never had any dropouts at all, The engineer said to blitz my downloads in the first 2 weeks as BT would cut my speed back if i didnt use it all, and it certainly looks to have happened, can someone please help
7/17/2013 8:13 AM GMT 87.114.***.* 35.84 Mb/s 6.60 Mb/s 16 ms London
10/8/2013 11:09 AM GMT 87.113.***.* 28.01 Mb/s 6.04 Mb/s 30 ms London
these are a couple of tests, and the trend has been downwards, for the first two weeks it was a stable 34-35 meg
Al

[#2]

Hi Al,
There's nothing obvious why your sync speed has lowered, I can see your estimated speed is 23.5Mb/s which you're still over.
It may be worth running through our faults wizard - http://faults.plus.net and complete the questions to see if this changes anything.

[#3]

Hi Chris, i was away on holiday for a month, when the connection wasnt used at all, when i cam back it had dropped to this, i know i was well over the estimated, as you can imagine getting 35 when your expecting 23 was BRILLIANT, but its on the way down now, so I would really like to get it back up there
, what concerns me is ON BT site, it says my line is set at 29.4, i cant understand why this has been set at that speed i was getting 35, with NO issues at all, no drop outs nothing, so why has it been set at 29.4, ?
Allan

[#4]

The BT IP Profile is set by the sync rate your modem achieves with the cabinet equipment (Sync speed is actually 1.033 times this value).
The increase in ping time suggests your line may have been interleaved (not uncommon after a while on FTTC) suggesting there have been a fair number or errors detected, interleaving on FTTC often reduces sync speed but improves stability (reduces errors).
People on higher sync speeds (50 to 70Mbit/s) often see a reduction of as much as 10Mb/s after some weeks or months of connection, this may also indicate increased crosstalk as more FTTC connections are made to your cabinet, some see a recovery after a further period of weeks/months but this behavior appears to be fairly common for FTTC DLM (Dynamic Line Management).
The fault checker should help to rule out a line fault causing increased errors.