"Rob" wrote

When I took them in for repair I asked the dealer to keep the old driver
and let me have it - they agreed.

When they phoned me to collect they said I could not have the driver after
all. The price quoted was an exchange price, and Dynaudio do not supply
drivers on any other basis. And that's what they said.

Then the dealer is in breach of his contract with you. You *could* sue him
for breach of contract and for the value of the old driver. But it's
probably not worth it!

Companies are entitled to supply parts on an exchange basis, many car parts
such as engines, gearboxes, alternators etc used to be available in this
way, but it should be made clear to you at the time that you agree to have
the work done.

David.