Just a quick update, I've tried both the resistor and the diode, both get rather hot, although the diode seems to handle it better. Done some checks with a TC and the resistor sits at around 80degC whereas the diode goes up to around 60deg. The ideal solution would be to change the PSU to a 48VDC, but with the current solution costing less than a pound I don't think I'll bother:)

T.