Hi, thanks for your replies
The glass is pink under halogen light (incandescent?) and a pale blue/lilac under the long life (fluorescent?) bulbs ? I had looked in 20th century glass definition of neodymium glass and thought it was similar differences? I have taken another photo without backing colour to detract, showing the blue/lilac effect more clearly, though it is a slightly richer blue tinge than the camera could pick up