Evolution of the ionised gas-mass and ionising luminosity are plotted as a function of time from the MCPI simulation. The ionised gas mass shown here does not include any gas that has been ionised previously, but was accreted in our control run at the same point in time. Thus the total ionised mass implied by our MCPI simulations is the sum of the ionised gas present at each timestep (shown here) and that subtracted from the stellar mass due to being ionised (Fig. 7).