My memory is hazy on this subject, but there was a presumption that a Trader couldn't be an "innocent purchaser" because he had access to the likes of HPI and was expected to use them - failure to do so was not a defence.

That meant that as the trader could not be considered an innocent purchaser, he couldn't have good title, so any subsequent sale was invalid and the owner (HP company) was entitled to recover the goods.

However, if the individual had bought from the trader in good faith he could be argued to have good title as the "first innocent buyer" and that was where it started getting messy and my involvement ended...