Ghost writer required for a series of childrens' stories

This project will involve writing 7 childrens' stories (950 - 1100 words) aimed at teaching children aged 4-7 key life lessons related to money management. Due to a number of current committments, I am unable to write these within the timeframes I have set, thus the need for a creative and experienced writer. I have an outline for each of the stories to be written (refer to the attachment for a sample) and the topics include stuff like:
The trip to Legoland - the gang learn about spending wisely
The hospital christmas carol - the gang learn about giving
The mothers' day present - the gang learn about earning a living etc.

The writing has to be fun, exciting and written in such a way that the children don't even realise that they are learning. Each story should also be accompanied by an activity sheet.

I am looking for someone with experience of writing childrens' stories, who can provide samples of previous work and who can turn this around very quickly. Someone for whom writing is a natural skill and who would find this to be a fun project.

I would want the person to write one story first and if I am happy with it, then they will commence with the rest. If I do not like it, I would just pay a flat fee of £30 for their effort.

I am on a tight budget and am looking to pay a fixed fee of £250 for the 7 stories. However, if the stories can be written as well as illustrated, then I will pay £400.

Please note that the stories will be based on a group of 5 children aged 5-8 and the same children will feature throughout the different stories. I would be happy with black and white illustrations. Please note that all written text and illustrations will be owned by me, thereby giving me the freedom to modify the material as I see fit.

I would be looking to have each story laid out in a format (possibly microsoft word) that can be converted into a pdf file. All work should be your original work. I look forward to hearing from interested providers. Regards, Marianne.