>>>> I am about to move house - a nice simple move, as we are upsizing
>>>> and the owner of the house we're moving to is downsizing, and has
>>>> bought our house - a simple swop.
>>>>
>>>> As I am moving within the same telephone exchange, and taking my
>>>> telephone number with me, and the other party is doing the same, in
>>>> theory should we be able to continue our broadband use without any
>>>> disruption to the service? She is with NTL, whilst we are Pipex -
>>>> obviously both lines are ADSL
>>>> enabled but I'm not sure what change BT will make at the exchange
>>>> on the day we swop - do I just take my modem with me, plug it in
>>>> at the new address and carry on as if nothing has changed, or do I
>>>> still need to notify my ISP?
>>> I'm no expert but since your ADSL service is provided to your
>>> telephone line/number if you connect your modem to another telephone
>>> line you won't be able to connect. Of course, you and your buyer
>>> could agree to use each other's ADSL connection. 
>>
>> That is an absurd suggestion.
>>
> Rhinoceros!
Now you really are being preposterous David. I suppose I have to spell it
out for you. Apart from the contractual difficulties that would prevent the
service being legally used by another person the connection settings would
have to be altered so each party knew the other's sign on details. In all
probability the two users would not be able to access their email from the
other ISP. Add to this the fact that neither party could be sure the other
was not using the connection for illicit purposes. Do I need to go on David?
The OP needs to make proper arrangements with his ISP and make sure the
vendor of his new house does likewise. The chances of getting it all
coordinated is small so he should be prepared for some downtime. Last but by
no means least the vendor is on NTL which is probably a cable connection
anyway!
Peter Crosland