1 I wouldn't do it.
2 I would start with this, and then give your position (your name is at the foot of the letter) and change it to - XXX, who works with you, recomended that I get in touch with you. I work for...
4 As we..., ordering soon is advisable.
5 let us know enquiries and let us know why the delay has occurred - and let us know why the delay has occurred