To get the final calibrated flux in Jy we need to multiply by a conversion factor or responsivity that is calculated by making observations of a compact planet such as Mars or Uranus; the planetary fluxes, corrected for the SCUBA beamsizes, are available from the Starlink package FLUXES (SUN/213) [9]. Note that the secondary sources used for the calibration of UKT14 photometry [10] will probably have different fluxes in the SCUBA wavebands, mainly due to the different beam sizes, i.e. these sources are extended at some level. This is certainly the case for the one source, N2071IR, that has been calibrated against a planet so far and the whole list may have to be re-observed.
The SCUBA photometry cookbook