We've travelled back in time to Roman days!

Your clue for the fourth location:

The next location is minutes away. You spot two familiar characters near the bath - a walrus and a carpenter?? You walk past them up a narrow lane until you come to a main road. Thirsty? You might want to look out for a juice bar. But not for a tall glass of OJ - what you seek is outside. Look very, very carefully. Two tiny mischievous creatures are hiding in plain sight.