Hi and thanks to all who replied. I was actually using Firefox and it had worked for all the other segments but not #2. I tried again using Google Chrome and it worked straight off and at a good download speed.
Having got all the parts I now have another problem similar to many people - unlocking it. I have used the Jetmouse Keygen 1.5 with my 1490T unit number XXXXXXXXXX and map id 2043. I would like to have used the sd card id but when I try to get it using the checksum in the service menu I get "0x00000000", which is not accepted by the keygen. This is not a branded sd card, just a 16GB generic. Does anyone have any ideas about unlocking the maps or is there anything I am obviously doing wrong? Both img and unl files are on the sd card in the Map folder. They have both been renamed to "gbdisc50kv2" and there other maps in this folder that do work. Any help would be appreciated.