Results of further evaluation tests of a monthly rainfall-runoff model used for extending streamflow data records in England and Wales are presented. In particular, since the objective of the record extension exercise was to make available long enough data records for reservoir yield assessment, model performance in reproducing the reservoir storage-yield-reliability relationship during calibration was examined. Finally, it can be argued that this type of test should be among the suite of performance checks on rainfall-runoff models in situations where low flow is the primary concern.