Complex sentence: The bakery and shop, which also had a post-office, were obviously built sometime after the village as the brickwork was of a different quality and in better condition than the cottages, exactly when it was built however is not know as it is beyond living memory.
Split into simpler sentences: The bakery and shop, which also had a post-office, were built sometime after the village as the brickwork was of a different quality and in better condition than the cottages. Exactly when it was built however is not known, as it is beyond living memory.