Factual error: Catus Decianus actually managed to escape from the massacre at Camulodunum and fled to Gaul.
Factual error: The dating of events is out. Claudius died in AD54, Agrippina was murdered (by Nero's soldiers, not by Nero himself) in AD59, Prasutagus died in AD60, the revolt began soon afterwards and ended in AD61, Nero did not marry Poppaea until AD62.
Factual error: Suetonius rushed straight from Anglesey to quell Boudica's revolt. He didn't go to Rome first - that would have taken weeks.
Factual error: There are numerous mistakes in the armour and equipment of the Roman troops. Roman infantrymen did not use round shields, although some auxiliaries did use oval shields. The Roman legionary's main weapon was the pilum (javelin), which he hurled before drawing his sword. Some of the soldiers in the last battle are carrying spears - carried by some auxiliaries but not legionaries - but no javelins are thrown as the Britons attack and there is no missile fire, although the Romans actually made heavy use of archers in the battle.
Factual error: All the Britons are clean-shaven. Most Celts at the time actually wore thick moustaches.