Discoloured leather sofa - tips?

[Helliecopter]

Hello
I've just inherited a sofa, armchair and footstool that was in someone's conservatory. The leather is badly faded and well worn but in otherwise good condition.
Has anyone got experience of recolouring leather, either DIY using the creams you can get online or having professionals do it? Recommendations or advice (or warnings!) much appreciated.
TIA