I later heard they used an output site that was less than ideal, with a history regarding a bomb scare. It was also noticed by members of 2 different radio amateur radio groups that are in the area. Some experienced desence on the 2m band right near that location due to the power from their TX being in such close proximity.

Managed to find a snapshot on Wayback Machine.
https://web.archive.org/web/20101224140449/http://blogs.rnw.nl:80/medianetwork/uk-radio-pirate-jailed-for-sparking-terrorist-alert

Can't find any other links to the story anywhere unfortunatly.