After leaving the office, Toby was approached by a man, javid, who was collecting donations for a local charity. Concerned that javid was someone he owed money to, Toby mistakenly thought he was about to be assaulted by Javid and so he pushed him causing javid to fall and break his arm.

Short full answer using IRAC to advise whether Toby can rely on the defence of self defence in respect of the injury cause to Javid.