Unknown Campanula naturalised on Plymouth Hoe

Unknown Campanula naturalised on Plymouth Hoe

Observation - Unknown Campanula naturalised on Plymouth Hoe - UK and Ireland. Description: This little Campanula looks to be naturalised on the limestone rocks of Plymouth Hoe. Can anyone offer to put a name to it, please? It is smaller in all its parts than C. portenschlagiana and C. poscharskyana which are familiar to me and grow commonly on

This little Campanula looks to be naturalised on the limestone rocks of Plymouth Hoe. Can anyone offer to put a name to it, please? It is smaller in all its parts than C. portenschlagiana and C. poscharskyana which are familiar to me and grow commonly on Plymouth's stone walls.