Done that job for years and I have a saying Jord, feck them in or feck them out. It's tough but rewarding, you just end end being bullet proof to the cr@p that gets back to you, thick skinned it works mate.
Did the big corporations quit when they heard no? Don't listen to the negatives mate. Keep up the good work, and yes Foxtons is a pet hate of mine too, knocked on the Chiswick door many times and had many meetings.