http://badc.nerc.ac.uk/data/ukmo-midas/ MIDAS Land surface and marine surface observations data from the Met Office station network and other world wide stations as stored in the Met Office MIDAS database
Unfortunately I can't find any match between MIDAS subhourly precipitation stations and NRFA peak flow measurements. The final dataset will merge daily rainfall, water flow and peak flow from NRFA.
Epic #51
Got access to: