1) this is a change to the format of a field on a layout. It will not change the data stored in that field.
2) In Layout mode. Select the field by clicking and then go to the bottom of the Inspector's data tab where you'll find a box that specifies the currency symbol and can change it.
3) Sorry, I live on the "other side of the pond" from you.
Thank you very much indeed for your help on this fantastic.