No artist would smoke inside a studio. The smoke residue would mess up the ceramics glaze during firing.
John Bonetti is being transferred from prison to London. We are told he had been held "on the moor", which can only mean Dartmoor Gaol. There have been no active prisons in Cornwall for many decades, and Bodmin Gaol closed in 1927. But he nevertheless escapes onto Bodmin Moor! This means that the private security company entrusted with transferring him is not only incompetent, but they are driving in the wrong direction. London is east of Dartmoor, Bodmin Moor is west.
Uncharacteristically sloppy police work in not charging Jane from the get-go with aiding the escape, or immediately putting a tail on her after hearing her romantic motive story. Though she was their best lead, they just let her roam free.