Forgot to add English spoken language endorsement to my UCAS application

The speaking element isn't vital unless you are an International applicant and using this as evidence of your 'language ability'. If you still feel you need to add this - if the school have not yet actually sent your completed application to UCAS, you can ask for the school to 'return' it you for this sort of adjustment, and then you just resubmit it to them. Or if they have already sent it to UCAS, then use this online form - Request to amend qualifications listed on your application | UCAS - and just email each of your Unis to tell them that you have done this.

Do you think it’s worth asking them to send it back? I’m afraid they won’t be able to send out my application before the deadline
For reference I’m a home student