Lately, my 83 diesel Westy has become hard to start in the sense that the key,when turned to start, does nothing. I can try it a couple of times and sometimes that works. Other times I may have to turn the steering wheel half a turn before it will start. 

Of course turning the wheel and having it start is circumstantial; would it have started if I had not turned the wheel?

From the symptoms I am wondering if anyone can say whether it is the switch or the lock? Or other?

Thanks,

Jim