With regards to Bela, Alvin could potentially be liable for assault occasioning actual bodily harm, contrary to S47 Offences Against the Person Act 1861.
Alvin committed the actus reus of this offence in the form of assault. He did this as a voluntary act (Hill v Baxter, 1958) as he caused Bela to apprehend immediate and unlawful personal violence by shouting very wildly towards her in a conscious exercise of will (R v Ireland, 1997). Bela suffered actual bodily harm as she fainted and was unwilling to leave her house for months afterwards, which interfered with her health an comfort and was not merely transient or trifling (R v Chan Fook, 1994).
In terms of causation, Alvin would be the factual cause of Bela's actual bodily harm as "but for" Alvin shouting wildly towards her, Bela would not have fainted and feel too scared to leave her house (R v Pagett, 1983).
(Entire answer not provided but was marked 24/25 overall).