You can get a room stat with its own timer, bit expensive but might be handy in this installation.
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=39276&ts=80136
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=17585&ts=80136
and others
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=39276&ts=80136
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=17585&ts=80136
and others