ADSL with an L2TP tunnel over Virgin cable isn't an uncommon arrangement amongst the A&A redundancy fiends.
You do of course pay for what you get...
Kim, I love it when you talk dirty like that I have no idea what you were saying, but it sounded impressive....
It menas you can use your AAISP internet connection via another ISP.
You can tunnel to AAISP from your home network via a 3rd party ISP, and it will behave exactly as if you connected over the ADSL.
Because at the underlying level, it is the same.
An ADSL connection is tunneling over BT's ( or Be's ) core network.
An L2TP tunnel via another ISP is just the same.
It lands up on AAISPs LNS ( Layer2 Tunneling Protocol Network Server ) the same, whichever way it arrived.
It's a seriously cool thing to be able to do.