I saw one of those helpful hint videos the other day showing how to get a snapped off key out of the lock. Maybe you can search for it on youtube?I forgot to mention the latest problem I have which unfortunately won't solve itself. As I was going out yesterday and was locking the front door the key snapped in the lock and is well and truly stuck.
It's too far in to try any of the usual ways of removing it but at least I can lock it from the inside and luckily I have rear access to my house so can use the door at the back of the house, but I may have to buy a new lock. My brother in law is going to see if he can sort it out for me - if he left it to me I'd probably end up needing a new door!