While dual pricing is a problem in our industry and there is no doubt that some organisations behave disgracefully, perhaps the FCA should look at the root cause of the problem.

As the vast majority of the market is driven by price, via comparison sites, bad behaviours begin to emerge. For insurers to get ranked into the first 5 slots (nobody cares after that!) on a comparators list, they have to remove virtually all of the cover and base it on "new customer only" pricing. 

The insurer loses money in year one and attempts to recoup in the following years, so the price goes up. 

The UK motor insurance industry has lost money for most of the last 20 years as a result.

How is this in the best interests of the client?

So, good for the FCA - fix the Symptom but also address the Underlying Cause!