The Tax Information and Impact Note (TIIN) published in July 2019 sets out that HMRC estimate that 170,000 individuals working through their own company, who would be employed if engaged directly, would be subject to the off-payroll working rules. Individuals may have multiple engagements through their own company, with some engagements subject to the off-payroll working rules and some not. Those who are complying with the existing rules should experience little impact. The TIIN can be found here: https://www.gov.uk/government/publications/rules-for-off-payroll-working-from-april-2020/rules-for-off-payroll-working-from-april-2020.
The impact of the delay to the changes of the off-payroll working rules will be published at the next fiscal event and will be subject to the scrutiny of the Office for Budget Responsibility.