Many thanks Stuart for your kind comments and yes Bradford was very much on my mind when I made my first posting. Bradford never had any routes where Coasting Brake Regulations were imposed. This was surprising as Church Bank, Whetley Hill and the hill to Faltis Square were all steeper than 1 in 9 criteria.
However I was wrong in saying Huddersfield had four routes with Coasting Brake Regulations as additionally there was the Longwood route which had two short steep sections where coasting brake regulations were lifted in 1949. This makes me think that short steep sections could be exempted so this maybe how Bradford was coasting brake free.
Another reason could be the improved rheostatic brake system introduced with the introduction of the new Series Dynamic and Rheostatic (SD) control system developed by the English Electric Company in partnership with Bradford in 1936/37 period with AEC661T no 634. The greatly improved control system (SD) became standard for most of the wartime trolleybus and post-war production and replaced the regenerative braking systems. By 1950 nearly all trolleybuses had better electric brake systems and were able to stop reliably on any steep gradient so some relaxation of Coasting Brake Regulations may have been possible.