The rest of England is littered with buildings containing reused stone and bricks from Roman Britain. All Saints Church in Brixworth, Northamptonshire for example is one of the finest examples of Anglo-Saxon architecture in England. The Anglo-Saxons used reclaimed Roman stone and brick tiles in its construction, material which is thought to have come from the Roman towns of Lactodurum (Towcester) and Ratae Corieltauvorum (Leicester). It became a Grade Iisted building in 1954, so that Roman building material is likely to remain in use for at least a few hundred more years.
So perhaps to answer the question, it is not so much what the Romans did for circularity and reuse, but what they did together with those that followed - the Romano-British left behind after the collapse of the Empire, the Celtic tribes and Anglo Saxons who eventually filled the void left by the withdrawal of the Romans from Britain.
Their first instinct was to turn unwanted structures into new buildings that better suited their needs, and make use of valuable building products on their doorstep. They had a natural instinct for reuse and repurposing, and a stronger drive and focus for this, more than perhaps we have today.