I currently work a four day week. Have been back post maternity for year and a half now. I offered to my boss that I could now go up to 5 days but on the basis of working that day from home. Boss has said no, that I can't have a regular set day from home. But that informally between me and her I can arrange home days, she indicated that once every 2.5/3 weeks would be fine. Reason is that it would be setting a precedent within the team. However this isn't strictly the case, a part time member of my team does one day from home, and so does my boss (pretty regularly). A person at a similar level to me but in a different team came back after maternity full time but with a regular one day from home. I have been in this job for a very long time and am well valued and feel pretty disappointed they haven't said yes. Have you experienced similar/had to argue a case for home work?