Surely asking my client for interest and compensation will lose their custom then?
Not in our experience. However from a purely tactical point of view the first thing you should consider when deciding whether to invoke this legislation is whether the claim for compensation and late payment interest will delay the payment of the principal sum. If you are very anxious to get a large sum owed to you into your bank account you will have to think twice as to whether you wish to aggravate the situation by making a claim for compensation when without it you may get paid without any fuss.