All as above, both great suggestions.
As for your query on handlebars, if you get a new (Ahead) stem you can either go for the traditional clamp size for a 25.4mm handlebar diameter or the more modern, beefier 31.8mm.
For an older Orange (not sure which year/model/size you've got), if you want to keep it a bit more original I'd be more inclined to stay with 25.4mm size with a nice Syncros/ControlTech/Orange SK9 stem, for example.
If your Orange is a 19" model (C-T) you'll need a threadless steerer of 190mm or above.
1990 Ridgeback 704XT 1990 Raleigh Dyna-Tech Encounter (SWMBOs) 1992 Orange Aluminium 'O' 1992 Orange Prestige 1994 Orange Clockwork 1996 Orange P7