I always expect reduced discount on VOR but it depends on manufacturer as to what I charge the customer. In my experience one of the worst is Rover where you only get about 2% even if the part is in stock. The only way you can give parts and labour warranty is to charge a little extra when there is no room in the RRP. I also do the same as Richard and point out the pitfalls of supplying their own cheaper parts (sub standard non OE, wrong parts delivered and warranty issues). Nearly always, they tell me to get the parts for them because they are either too lazy or lack the confidence to talk to parts suppliers. You also have to remember that it's swings and roundabouts here. My mark up on a wiper blade is about 200% and I bet most of you are doing the same with parts like that (bulbs, oil, filters etc).
regards to all, Bryan.