Two phone lines in the house, what to do.

[#1]

House has two phone lines in it, both fitted at the time of build (25 years ago).  One has plusnet adsl, giving me around 7000K download, and 44db att.
The "other" phoneline is seldom used anymore, but it *IS* the main house phone number,and everyone knows it.
We don't really need two phone lines so I'm looking to "downsize", use one line for both phone and broadband.
I've had my plusnet account for years, my email is widely known and I don't want to change it.
questions.
1) Can a broadband line/account be moved to a different line within the house, so as my account name etc is un-affected.  what are the implications in doing this, does it cost money, what is the plusnet term for this type of move.
2) If the above isn't possible, is it an option to get BT to kill my "phone only" line and move the phone number to the broadband line, and if so does that have any implications for my plusnet broadband.  If its possible what do i tell BT/Plusnet to acheive this ?
3) For some reason, The kitz line checker is telling me that the line currently being used solely for a phone, is only capable of 4000 on adslmax or adsl2+, whereas it more or less tells me the correct figures for my current broadband line (and confirms that broadband is already on it). What I don't want to happen is for the broadband to move to the other line and then find out I'm getting less bandwidth. Anyhow how can the two figures be so different when the lines are in the same house, were fitted at the same time, and go to the same exchange.

[#2]

Hi tangey
1)  I would have thought that this would be just a normal house move.  I know it's in the same physical property, but everything else is the same as a house move.  I would have thought this would be free if you commit to staying for 12 months, else there would be a fee.
2) I think this is possible, though it may need a bit of manual work.  Mand is probably the best person to advice on that.  One of the Digital Care guys is probably around before too long.
3) It is certainly possible for the 2 lines to get very different speeds on them.  The length and the quality of the line determines how fast broadband would be on the line.  It's possible for the 2 lines to take totally different routes back to the exchange, with one being much longer than the other.  It is harder to estimate the speed of a line which hasn't got broadband on it as the stats don't exist to make a good guess from, so it may just be that.
Phil

[#3]

It's probably going to be organisationally easier to move the broadband even though changing a lines phone number is theoretically just a few keypad taps for BT.
This is because basically the line comes first and the BB is added to it.
After you've moved check the stats and if speed is acceptable cease the other line.
If it's unacceptably slower then you can "try" to get BT to swap the line pairs as a "repair", otherwise I guess it gets complicated.

[#4]

Quote from: HPsauce

...... changing a lines phone number is theoretically just a few keypad taps for BT.

It probably would be rejumpered as BT would assume that all services would want to be retained, i.e voicemail, call divert etc etc. If they did it by keyboard then these services will not be transferred.

[#5]

Quote

2) If the above isn't possible, is it an option to get BT to kill my "phone only" line and move the phone number to the broadband line, and if so does that have any implications for my plusnet broadband.  If its possible what do i tell BT/Plusnet to acheive this ?

imho this is the best method to do this.
Getting in touch with PN directly, and they should be able to guide you with what you want to do. (Both phonelines could take a different route back to the telephone exchange, it really is a flip of a coin if its going to be better or worse.