maybe Markie can say how it worked?
Sorry, missed this.
In the case I know of, the letter was written for and in the name of the person concerned (the patient, for want of a better term), but by someone else. The patient was not capable of writing such a letter themselves. The letter noted this, and requested that the writer be allowed (not that they had ever been refused, in fact) to attend all meetings and appointments with the patient.
Writing to her MP is a good call but time is of the essence.
If you write to her MP via http://www.writetothem.com/ then they will have it in minutes. That doesn’t mean an instant response, of course, but it does put that iron in the fire – and you can tell people that you have written to her MP and will be feeding back details from whatever meetings / conversation you are then having.