1. A computer implemented method, implemented in a device comprising at least one processor configured to process data to provide frequency information and at least one memory, for determining one or more anomalies associated with a first set of data, said method comprising: processing, by the processor, said first set of data to provide respective frequency information for each of a plurality of combinations of data in said first set of data, said frequency information comprising a number of times each respective combination of data occurs in said first set of data, wherein said first set of data comprises a plurality of data entries, and wherein a combination of data comprises a combination of data elements forming at lest part of a data entry in the set of data; comparing said frequency information for the first set of data with frequency information for said combinations of data in a reference set of data, said reference set of data comprising data of a reference interval; and in dependence on said comparison determining one or more given combinations are anomalies based on a difference in frequency information of said given combination for said first set of data and said reference set of data.