Are there many 'sole traders' who have employes.
One you employ people you have to Register your 'Business name and address" (Note : NOT COMPANY name) with HMRC as an employer, take out employers liability insurance, set up a pension plan for your staff, pay holiday pay, deduct income tax and NI at source, pay a minimum wage, issue contracts of employment, be responsible for their training and development, and keep up to date with employment law, amongst other things.
A sole trader is totally reponsible for all of the companies actions (hence the name) - you are the ONLY person who can make decisons, employing staff is such a time consuming faff that it leaves little time to actually run the company let alone do the actual work you set up the company to do.
I am glad we closed down the businesses when I retired in 2005 - it was becoming a nightmare even then.