Here is the link to the Consent Form:
https://
assets.ctfassets.net/xxg4p8gt3sg6/2G0GtF7WPLvzToKOfompkv/c03d754f3eaf210cf115e35a9bfd096b/VFS-ConsentForm.pdf
Highlight the words in bold and put it in your search bar to access the link. If you cannot access the link, go to VFS Global Lagos website, click on "Apply for Visa" (its a tab across the top), go to" #2 Begin Application", move down to the last paragraph in this section and you will see the words "consent form" underlined in red, click on it and it will open the document for you.
You must print and sign (original signature) on Page 2 and 4, then add this Consent Form to the package of documents you are sending along with your passport.
For payment regarding return courier and other information go to VFS Global Lagos website:
https://visa.vfsglobal.com/nga/en/can
On the website, at the bottom of the first page there is a tab "contact us" giving an email address and telephone number for help which I've added below. They are quite good at responding within 1-2 days to emails, and not usually good at picking up the phone.
info.cannig@vfshelpline.com / tel. no.: 2348150199900
I did not use Lagos but these are the same steps I took. I only knew to add the consent form from reading another thread on these forums, so am happy to pass along the knowledge. Best wishes again to you.