Simulation of inverting Op-Amp
I am trying to build a circuit which is controlled from an analog
  input signal Vin to produce a -24V signal with >50mA output.


To produce -24 volts from an op-amp means that it has to have a negative power rail because an op-amp cannot conjure up any voltage that is outside the range of the power rails and, your negative rail is in fact ground (0 volts): -



The MCP6V51 is a rail-to-rail output device so, if the negative rail were (say) -25 volts you could expect -24.9 volts at best.

To produce circa 50 mA requires a more specialized op-amp because the MCP6V51 cannot normally be expected to deliver more than a few mA - it has a short circuit output current of -36 mA and, under normal load conditions, the data sheet implies about 5 mA in the table on page 4.