Hi robbiegy2k,
sorry not been able to get back to you a bit sooner - first some precautions -
don't go round disconnecting wires from 2 & 5 without being certain how all the extensions are wired. If they are series wired ie master to extn1 to extn2 to extn3 etc and you use extn6, there is no point in disconnecting anything more and if you do then the later extensions won't work! BUT the wiring you mentioned, blue on 2 (if you look carefully you'll see it has a white tracer, an white (with a blue tracer) on 5 indicates your internal wiring is to the modern CW1308 standard and is OK but you should check that is what you've got from the master to the first and at each extension.
Next, whilst playing with wiring and filters/phones plugged in etc, power down the modem/router and leave it off until you have finished. You can unplug the filter / line cord from the modem/router or remove the master faceplate to access the test socket, a few minutes after you've powered it off. It's best not to do this (off/on) more than 5 times in any hour and then I'd suggest leave it alone for the rest of the day - this is to avoid the exchange DLM thinking you have a line problem and raising the Target SNRM (or keeping it high). You can of course leave it off for longer periods without a problem, but if you already have a raised Target (as in your case) it's best to switch on in the day (more than an hour after sunrise and an hour before sunset) when noise levels are usually lower, also don't switch on if there is static from lightning around.
There is no point in considering ADSL2(+) (from any supplier) until your line/wiring/noise issues are resolved - you can end up in a worse situation.
You haven't confirmed the colour of the incoming wires to the master or whether it comes straight from the BT pole. If it is cable to the latest standard, CW1378, it should have 2 pairs (orange & white, and green & black - there's also 3 steel reinforcing wires but these will be snipped off when the sheath is stripped back), one of the pairs will be used to connect your line. You mentioned a landline problem a few months ago and they checked the cable to the pole - just because it worked doesn't mean that it is to an acceptable standard.
Now there's 2 things you've mentioned a) your line attenuation has been 48dB from day 1, is that since joining PN or previously with Be as well?
b) You've mentioned your line is "noisy". Is there an audible noise that you can hear on the phone?
What modem/router are you using?
If there is audible noise on your phone line, it's important to get this sorted first - a duff phone line will give duff broadband. First, you must eliminate any internal causes (otherwise you could get a big bill from your supplier due to OpenReach charges!).
Faulty wiring, filters, modem/router, cordless phones, or a bad connection can all be possible causes. Any of those or too many or low quality filters can cause broadband speeds to be poor and sometimes higher line attenuation than in reality. You only need filters plugged into sockets you are actually using.
It's important to work logically and methodically when testing and to use a corded phone (known to be good - check on a friends line if need be, cordless phones should be switched off and unplugged) and also using a quality "rat's tail" type filter such as the BT MF50 - a lot of filters that look like solid block splitters are poorer quality.
Ideally, initial testing should be done from the test socket, behind the faceplate of the master NTE5A (this isolates all internal wiring). If you do not have a Linebox, and only have an old style master, then test at the master and if you have extensions - unplug everything else (in all cases noting the precautions mentioned in para.2 above).
You must not tamper with BT's wiring (behind the rear plate of an NTE5A) or at the back of an old style master. In the latter case, if you have extension wiring you want to isolate and you are not adept at such things / have the right tools etc. leave alone or get a friend who is adept to disconnect the extension wiring. If you have more than one extension, you could disconnect the others at extn1 to avoid disturbing BT's wires and as best you can visually inspect the wiring to the first extension to ensure there is no likely physical damage.
First, plug the corded phone direct into the Test socket and listen for any crackling or other intermittent noises. If anything, you should only hear a very very quiet, barely audible gentle "shhhh". Anything else and you have a line problem. Phone your line supplier whilst it is crackling etc., don't use any automated testing. speak to an adviser, get them to confirm they can hear the noise and log it, and log it as intermittent and request that info is passed to OpenReach. Don't mention the broadband (you'll get the run around) if they ask about broadband and if you have a problem just say not as far as you are aware!
If the phone test is OK, then plug the filter and modem/router into the Test (master) socket (leave the phone out for the moment). Check you ADSL Line stats immediately after powerup (Connection/sync speed - that's not the throughput speed from a speedtester, Line Attenuation, Noise Margin - SNRM and Power both Downstream - DS and Upstream - US). Note the figures then plug the phone into the filter. If there is a noticeable change, the filter may be faulty. Check for phone noise at each stage. If there is no real difference from your normal figures, try a different filter, if still the same, then try (borrow) another modem/router.
If initial tests are OK, then test all your other filters here first. If all OK then procede to check your extensions/wiring.
Hope that all helps, post back any info that may help with suggestions, and post back testing results when you can.
