No is the short answer.
If this uniform is a specific expense incurred in the performance of their employment, its called Schedule E expense (not flat rate expense). The employer either re-imburses the employees or the employees can reclaim it on their tax return.
In any case, it would come under the small gift exemption to PAYE of €250 which an employer is allowed gift an employee with each year. Just put it down as a Dunnes voucher and give to all employees.
Patrick