Colonies of colonies - plausibility check?

  Well the nearest I can think of was that frequently in the European colonial period colonists often set the pace in pushing for further expansion against the wishes of the metropolitan government.  For instance during the early Spanish conquests in the Americas assorted conquistadors often engaged in campaigns of conquest despite the wishes/instructions of Madrid and at least some times in defiance of orders from their local superiors in the new World.  Later Spanish attempts to avoid abuse of the locals were often ignored with widespread use of forced labour.  Quite possibly something similar occurred with the assorted Portugese and later Dutch activites in the Indian Ocean?

  Similarly with Britain as far back as the 1760's the other big issue between London and the colonies was that Britain had sought to secure the Indians against violent seizure of their lands to try and avoid further conflict.  In Australia land was often seized in defiance of instructions from London and also in southern Africa.  IIRC Paris similarly had a problem with their commanders - as settlers were somewhat fewer - in the period ~1871-1900.

  Possibly the best example might be with India as you suggest.  For the 1st part of the Raj it was after all a private company, the EIC, formally in charge at at times at least local commanders seemed to have taken actions despite instructions from London.  Also I would suspect there were cases were local rulers in the area, formally under a British 'protectorate' sought to take advantages of weaker neighbours - although this is more opportunist actions than colonies distant from their 'homelands'.

  Also if you go a bit further back I think in medieval and classical times local regions of empires - whether Persian, Roman, Byzantium and assorted Asian ones - saw groups or commanders going for conquests without permission/support from their formal superiors.