What is a reasonable response time to email

[nerf54]

For context, it is to my employer requesting my P45 and confirmation of any holiday pay due to me as I am not returning from maternity leave.

My boss is notoriously useless at keeping up with his emails but no direct telephone number as it is run by a group. I could email the group HR director following up but unsure what is reasonable waiting time.

A week maybe - to send another email to him and then I’d probably do one more email to him a few days later before escalating

unless you need it more urgently obvs

Have you had your final pay from them? You won't get your P45 till you have