Ah. Is that expected according to
http://www.samknows.com/broadband/broadband_checker
If you're doing a lot worse than expected, maybe a bell wire breaker (I-plate) could improve things, if you have extension wiring.
And have a good check for any missing microfilters - the base unit of a cordless set is one I've seen forgotten, also answering machine, extra bell, dialup modem - and, of course, Sky box.