a phd is all about flexibility. i hate labs cos i cant get n e work done. I also suggest you get a life Stu rather than revolving ur life around this forum...it seems u think ur some know-it-all who hasnt even started his phd yet. You dont own the forum!
Your supervisor is probably concerned that you won't get enough work done outside of the lab due to distractions. Why don't you suggest a trial period to try it out with fixed lab and fixed home days. Also suggest regular meetings.
I have to meet up with her once a week. I dont mind going into labs its just that i know that i would have to work double at home in order to make up for not doing enough at labs. The trial period is a good idea. I think I might only go in on some days.