bt Upload Speed limit of 448 compared to bethere etc

[#1]

So i understand plus.net is tied down to BTs packages and I also know about the upload you can do to get 8xx kbps for a extra £8....
but there still not even close to the upto 2.5mbps that bethere is offering... at the end of the day its the same technology. So why have they no implemented a higher speed. Is it simply because of the lack of demand?

[#2]

It is not the same technology. The BT 20CN & 21CN network uses ADSL Annex A which has a maximum theoretical upload speed of 1.2Mbs. Be and some other LLU suppliers can decide to install ADSL Annex M equipment which gives them the higher upload speeds you have quoted.
This is not something that Plusnet can change... it is a BT limitation.
Trials of annex M have been done but it is not something that BT are currently planning to roll out.
You can get faster than 448Kbs on the ADSL2+/21CN* connection. This still uses annex A but you can ask for the upload cap to be removed at no cost. This can get up nearer to 1Mbs depending on your line quality.
Check your exchange and see if it is enabled for ADSL2+... if it is you can request to be moved onto it*. Many people already have and Plusnet are moving people over in batches at the moment.
and there is also FTTC in some areas... then you can get up to 8Mbs upload speeds.
* you will need an ADSL2+ capable router.