Once a final financial settlement has been reached, whether directly between you and your partner or through the courts, that would usually be the end of the matter. It will likely contain a clean break clause, preventing you from making any further claims against your partner’s assets.
However, if your partner did not disclose all of their assets when that settlement was reached, you may have grounds to re-open and re-negotiate the settlement. You would need to make an application to set aside the order. You would need to prove to the court that your partner did not give full and frank disclosure and that if they had, a different financial settlement would have been reached. If your application is successful, you could claim the costs associated with your application against your partner so they would need to pay your legal fees. There is also a risk that your partner could be held in contempt of court, which is punishable by committal.