It depends what you mean by West London- that covers anything from Central London to where I am out near Heathrow!
Am sure someone else can advise on Central West London but as far as the western outskirts 80% of my bookings are incalls, though there is a market at the Heathrow Hotels. I can go long periods without any outcalls though- but I do just do hotels, I turn down bookings at client's homes- if you choose to do that there might be more business.