Ubuntu has let me down again, for the second time in two months.
The menu bar and launch panel have disappeared. By some ingenuity I managed to get a web browser launched, and searched for a solution to this problem. It turns out it is a common problem, and many solutions are suggested by people out there. But sad to say, none of them works for me.
So communication will be sporadic until I get back to St Andrews next month (unless anyone can provide me with a solution that does work!)