I've checked out the router, and it seems I'd slightly underestimated the connection.
Here's the raw stats from the router:
Maximum Bandwidth (Up/Down) [kbps/kbps]: 1,036 / 8,224
Bandwidth (Up/Down) [kbps/kbps]: 448 / 7,680
Output Power (Up/Down) [dBm]: 12.0 / 19.5
Line Attenuation (Up/Down) [dB]: 23.5 / 42.0
SN Margin (Up/Down) [dB]: 21.0 / 6.0
The checker website reckons it should get 4Mbps to 6Mbps
, however a speedtest reports 3.52Mbps down and 0.38Mbps up
The exchange is not currently included in those that have been requested for an upgrade, but I'll get my Dad to register his interest.
Thanks for the help.