This very much depends on the area and what room is being wallpapered. For example a Kitchen or Cloakroom can be a lot more awkward and tricky than standard box room.
To hang a Feature wallpaper would cost approximately £95.00 to £150.00 Labour Only
Another factors to consider is the type of wallpaper to be hung for example is it standard vinyl, wide vinyl etc. also does existing wallpaper need to be removed and the wall prepared before hanging the wallpaper.
Some Decorators may charge to hang wallpaper per roll which on average can be approximately £25.00 to £40.00 a roll, however this can increase to £35.00 to £70.00 If it's a mural or a paper that requires more time ie- extra wide paper, Wilkinson’s or Laura Ashley and so on.