Another question now.
The engineer has been this morning, taken away the set top box that was used for broadband (it wasn't really being used for anything else so I've stopped paying for it) and replaced it with a modem. The connection is fine, but the speed of it seems to be exactly the same as it was before -- I upgraded to XL Broadband when I asked for the new internet, as obviously I was on a very slow connection through the STB.
How long does it take for the increase in speed to take effect? Should it have been as soon as the engineer finished the job and set up the new modem or do I have to wait for something else to happen in the background automagically?