Naive Pastel Portrait of Young Woman with Wonderfully Coiffured Hair

This pastel portrait would I think date from her costume to the early 1800's, possibly 1840. There is a naivety to the quality of the drawing, with the simplicity of her hair and her dress, but her face I think is quite beautiful and quite fine, with those fine dark eyebrows and almond shaped eyes of deep blue and that little mouth matching the same colour as her dress. She is certainly attired beautifully, her hair arranged in what could be called an Apollo Knot with that wonderful comb/tiara placed on her crown and with those two dark ringlets falling on either side. Her Empire Line dress is set off perfectly by that wonderful shawl with just that hint of colourful embroidery at its edge. She is seated in front of a wonderful vibrant blue background which lightens from the grey blue at the bottom to a sky blue at the top. The portrait sits in a gold painted wooden frame, which is certainly not the original one, but from the label on the back and the format of the London telephone number (active between 1958 and May 1990) I think would date to circa 1980.