to think that a lot of teachers are a tad patronising..

[PatButchersEarring]

..and have a tendency to talk to their peers as though they are schoolchildren?

I mean, don't get me wrong- teachers do a fantastic job. It's just that it seems to be that a high proportion of them don't seem to be able to switch off their supposed superiority at the school gates? Is this a common occurence, or is it just some of the teachers which I happen to know?

Actually I agree with this. (And I usually go into defensive mode when it's a teacher thread.)
I am a teacher in a strange area - the town itself has areas of significant deprivation, but the surrounding villages are affluent.

Many of my teacher colleagues talk about our parents like they are scum. Many of them (the parents) don't get it right all the time, but the condescending attitude from the staff irritates me to hell. Many of the teachers won't even make the phone calls home, they just leave it to the office staff.

I get snidey comments for living in said town and GASP seeing some of the parents when I go out and TALKING to them! I can't stand it.

I used to teach, I used to find myself doing that from time to time. Teacher Mode becomes second nature and sometimes you forget to turn your work persona off, or if you're distracted you can slip into it without realising. It's not intentional, and it's pretty embarrassing when you catch yourself.