Hi, firstly apologies for the scant details, this was all done in my absence and not by SQL people.....
While I was away the network admin realised he needed to resize the partition that the transaction logs live on.
He used sp_detatch, did his thing with the partition (drive letter and path remained the same), restarted SQL and reattached the DBs.
Everything seemed fine until users started doing certain things in the 3rd party application (SQL backend) and they started recieving coallation errors (coallation same as ever was and always working prior to log move). Apparently a restore of the previous nights (prior to log move) backup of MASTER fixed the problem.