Madhurisan,
Basically the correct expression is ; つまらないものですけど、差し上げます。It is indeed used in formal settings, but I am not quite sure about the usage by adult only.
Of course, when I used nobody objected, but they were happy that I am using 警護 correctly. Our students are going to use the language in business world, so they can use it surely.
Let us confirm it with a Japanese person.
Regards,
Vrinda