Jury Service

Client has asked me to verify the loss of earnings of his wife who attended jury service. W works as a supply teacher on a irregular basis. When W does work the employer takes her on their books and pays her as a temporary employee. W has never worked as a sole trader nor LTD, she's only worked as a contracted employee. W's day rate is 120 pounds but the court will only pay 60 pound a day. W wasn't contracted to work at the time of jury service but was looking for work. Last employer will not verify her availability for work nor her day rate for the purpose of making a loss of earnings claim to the court. H has asked me to verify W's salary for a loss of earnings claim. Is this permissible? W isn't a client of mine but all I would be doing is independently confirming her hourly rate based on previous payslips? Can you see any problems in doing this?