Sending part exchanges to the block?

[AutoJacob 34]

Evening,

I'm wondering what's everyone's opinions on the rough / faulty part exchanges? Up until now I have sold them on a trade sale only basis, no warranty, no returns. Recently we've had more and more headaches from complaints and people being unrealistic for the peanuts they are paying so today I woke up and thought I'm going to enter the 3 part exchanges we have left and just set the reserve as our cost price and see what happens.

03 zafira, nice mileage 91K, needs a good clean sold provisional £225, reserve £250 but bear in mind these bangers normally make £600 at BCA.

03 Sport KA Convertible mint condition in Red, nice mileage 70K, valeted and a nice drive £375, reserve was £250.

06 Astra 1.8 SRI, 100K mileage, 12 Months MOT bit rusty looks like it's been living under the sea with sponge bob for a few years but still OK nothing major, reserve £600, £400 sold provisional.. again these normally make £700 - £800 at BCA with rusty arches and sills like normal.

Let me know you're stories and how it works for you.

As always any help is appreciated