Under what circumstances could a bank disclaim vicarious liability in respect of a cheque issued by a branch? In fact, it wouldn't even be vicarious, since surely a branch is not an independent legal entity separate from the bank itself.
In other words, the difference sounds like it's as insignificant as might be the colour or size of the paper it's printed on, the effect in terms of what matters, namely the payment guarantee - unless stolen or forged or the manager has been forced to sign it at gunpoint or by blackmail/kidnapping etc - would be the same.
If not, what is the real difference?