Missed document checklist while sending pbs dependent child application

Hi,

I am an Indian national residing in UK and today I submitted document for son who is born in UK by post. After posting I realized that I have not posted document checklist in the bundle of document to UKVI. My question is, can this cause visa rejection? can I send a separate post giving reference of my actual post about missing document? Will they accept.

Please help in this regard in understanding the process.

Thanks.