Trying To Be Creative Again

Bored at work again, I am desperately trying to spark the creative juices by working on an idea I have for a children's television program. It is an idea that I had years ago, but back then it was just a name and the whole idea was based around that name. I don't want to give too many details away, in case everyone thinks it is a really naff idea as much as that I don't want someone to steal it.
I have been trying to write a script for it, my first attempt since playwriting excercises at school over 20 years ago! I'm not finding it easy. I don't actually feel confident in my writing ability, especially as I have always had difficulty in writing dialogue (a pretty essential skill when writing a script, wouldn't you say?), but if it is the only way to get the idea seen I need to try it.

Being a children's program, aimed at children aged 7-11 primarily, and being animation as I want it to be, it needs to be light hearted and fun. Unfortunately, with the situation at work and my lack of writing experience, the writing isn't coming along very well. I don't think I am in the right frame of mind at the moment.
So, I thought I would focus on trying to find out the best way of getting the idea sold.

Do I just write to a production company with the idea and hope for the best?
Would I need to write a full script, or just have the bones of an idea and some of the characters?
Do I need to work out the whole package, i.e. costings etc, or would that all come later from the production company (I'm guess it would).
I really have no idea.

So, I thought that I would check out one of the best animation companies that I know and looked on Aardman Animation's website. There was no "contact us" section that I could find. I have found the BBC's Writer's Room website which is quite extensive, but I have yet to find a section about writing for kids programs, just the occasional snippet. I did notice however that it states that the BBC require full scritps, so that is part of an answer. I guess I will just have to keep looking. I do have the rest of the night AND 2 more night shifts to go.