This traffic is now confirmed as ceased. In recent years the traffic has been run with a dedicated fleet of five MBA 'monsterbox' wagons and a bit of digging today revealed the following:
The last time all five loaded wagons departed from St.Blazey was in train 6C39 on 8th November 2013. This was also the train that conveyed the last discharged fuel tanks from Long Rock. The loss of the fuel traffic seems to of left it uneconomical to run a service just for the scrap. After the five wagons last left loaded together back in November DB Schenker only managed a further trip on 17th January 2014 when just two wagons left tagged to the clay on 6C55. The empty wagons found their way back and all five languished at St.Blazey during the recent Dawlish closure. Then last week, on May 2nd 2014, the five wagons left St.Blazey for Newport EMPTY. The traffic has finished, and the 'grab' that was based at St.Blazey for loading as been removed.
Regards Nathan Many thanks for this information, keep digging.