You like how it is now? i think we can aim a bit higher than that. It is a bit broken tbh - the frontage is badly designed, messy and not nice for pedestrians use. It hardly gives a good first impression of Forest Hill.
That much space does not need to be given over to cars in inner London. There is definitely space to make that frontage nicer, prioritise pedestrians (who are the majority users of the station) and keep a car park for those who absolutely need to drive to the station.
I have no axe to grind with FH soc or their detractors - I am just someone who uses that station a lot and found it has been a lot nicer to use during the experiment.