The niche that was filled by the BE line bonding service is back again after a pause in taking new orders. Line bonding using ADSL2+ (with Annex M option) gives the potential for an up to 44 Mbps downstream, and up to 5 Mbps upstream service. Of course the usual world-wide rules of physics apply, so any speed is dependant on line length.
The £65 a month service, does require you to be paying voice line rental for two telephone lines from BT Retail or any other Wholesale Line Rental (WLR) provider, BE supplies the bonding router which is paid for in part by the £85 connection fee. A twelve month contract also applies.
Line bonding seems antiquated, but for those running a business and unable to get business service from Virgin Media, or cannot afford the price of a Metro Ethernet solution it can offer an improvement over standard ADSL2+ until such time as fibre roll-outs catch up. The doubling of the upstream speed is potentially the most appealing aspect of the project, as this allows for quicker uploading of pictures/video and improved remote access. While Annex M (the up to 2.5 Mbps) upstream speeds tend to favour shorter lines, the standard up to 1.3 Mbps of ADSL2+ generally holds well for longer lines, certainly 42dB (3.5km of telephone line) should manage around 0.8 to 1.1Mbps, and bonding obviously would almost double this.