nelliesmum, just wanted to add a few more thoughts.
This thread (quite a long one) is worth a read. It is talking about disciplining a 5 year old (different to a 2 year old), but the posts towards the end (esp by F&Z) are worth considering.
I use the door holding technique, but what I should have said in my post on this thread, is that I use it quite rarely.
I think it is quite easy to fall into a system of default punishment routines (ie naughty step), you think this is what you have to do, because child care experts say this is what you have to do, and you perhaps stop using the problem solving part of your brain.
Door holding, naughty step techniques are useful, but imo should be used rarely and along side loads of other things you can do to stop things deteriorating into red faced shouty melt downs.
How to Talk so Kids will Listen, and Listen so Kids will talk, is a good book to read. Although most of the tips in there are for using with older children, the concept is still good (and quite radical) that you do not need to resort to threats and punishments the whole time. Often rephrasing a request can diffuse a situation entirely, without the need to resort to a win-loose situation.