Sodium Chlorate hasnt been available for at least 6 years. Best you can hope for is Roundup Extra Tough or SBK.
White chippings go green by the end of the first winter - sooner if north facing. Small - less than 15mm chippings are a PITA, they stick in and on shoes and get transfered onto adjacent surfaces and indoors. 20mm + is much more user friendly. Either a coloured chipping, slate scree (not the fine stuff) pebbles (smooth rounded) or Gravel (angular shape) is best
The council can not stop you paving or graveling your front garden provided you do one of two things
You collect all runoff and direct it into a soakaway if using a non-permeable material - Tarmac, concrete, paved or block paving/sets.
If you use a permeable material like gravel that will by its nature minimise run off and allow the water to drain through arguably better than a grass surface