I have been absent from work on sick leave for several months (receiving SSP) usually working 3 days a week and not expecting to return for about 3 months.I'd like to return as a volunteer for a few hours per week as my mental health is badly suffering but my employer says i can't as the duties wud be the same as in my paid job albeit a lot less hours, about 1 or 2 for a couple of days per week. Can my employer do this? If so can i volunteer elsewhere?