As per the NOTAM;
AUS 07-06-0207/1706/AS2 GPS SIGNAL JAMMING TRIALS. GND JAMMER LOCATED WI 0.5 NM OF 5016N 00516W (PORTREATH, CORNWALL). ACTIVITY MAY AFFECT ACFT WI 6NM RADIUS FLYING BELOW FL300...
They ran a similar trial out of Sennybridge very recently, also well NOTAM'ed. Nothing untoward was noticed at all during the notified period even when flying well within the reported radiating area.