I had a set of 5 inertia reel belts fitted because I carry passengers of various sizes and ages and it was a TOTAL pain trying to adjust the belts all the time, plus I was really unsure about how safe the old belts were. (They are available if anyone wants them - a set of 4 original 1970 - aircraft type (grey) fronts and factory fitted rears (black)). Very pleased with the new belts although the anchor positions had to be changed. They were installed by Quickfit who were very efficient, but not cheap!! But then I took the view, what price safety.
Interestingly the installer said that some of his customers insisted on illegal installations for display, but the car was never driven on the road. What a waste I thought - I drive the Duchess at every opportunity. Why have such a car if not for the pleasure of driving?