According to the DfT Circular 1/2002 which is the Gospel for Public Safety Zones :
"Careful attention should also be given to the location of major road junctions and to related features such as traffic lights and roundabouts which may lead to an increase in the number of stationary vehicles within a Zone". This guidance applies even in the somewhat less-hazardous 1:100,000 zone.
And perhaps the same level of care might be exercised in framing LBC's policies in this area?