In the Brightbox router under DHCP settings, have you reserved the IP address for the TP-Link wireless adapter?
Example: My Windows XP computer wireless adapter card is configured with IP address 192.168.1.13
I have windows configured... Use the following IP address:
IP address 192.168.1.13
Subnet mask 255.255.255.0
Default gateway: 192.168.1.253 <-- my router IP address.
Use the following DNS server:
Preferred DNS server: 220.127.116.11 <-- EE/Orange DNS server address.
Alternate DNS server: 18.104.22.168