“… the earlier an admission is made in the proceedings, the greater the reduction which will be appropriate. Consistently with the approach taken in criminal cases pursuant to the Sentencing Council’s definitive guideline, we think that a maximum reduction of one-third (from the term reached after consideration of all relevant aggravating and mitigating features, including any admissions made before the commencement of proceedings) will only be appropriate where conduct constituting the contempt of court has been admitted as soon as proceedings are commenced. Thereafter, any reduction should be on a sliding scale down to about 10% where an admission is made at trial.””