I had the first problem on my MK1 recently, turned out to be the dimmer switch, play with that and see what happens, if they flicker when you play with the dimmer then you need a new switch ot need to service the one you have.
After reading your second problem it seems you may have a loose connection block in the back of the fuse box, this may actually be the same problem affecting the above rather than the switch...
First port of call would be chck the connections at the back of your fusebox