My company has created a corporate video for a client without signing a specific copyright agreement. Despite the lack of agreement, I have no issues granting copyrights to the client. But now the client approached us saying we should remove a 20-second excerpt of the clip (total length 4 minutes) which is shown on my company's website as part of work portfolio.
Obviously, I'm not happy about it and would like to (nicely) explain to the client that I have the rights to showcase my work. The question is, though, am I right? Can I claim this as 'fair use'?