As long as you can get the olive fully onto the copper pipe, even by a couple of mm, then it'll be fine.
Having just measured one with a pipe and olive in it, with a 25mm pipe you will have 3mm of pipe past the edge of the olive, more than enough for it to be ok. Just use a copper olive and don't over tighten.
Having just measured one with a pipe and olive in it, with a 25mm pipe you will have 3mm of pipe past the edge of the olive, more than enough for it to be ok. Just use a copper olive and don't over tighten.
