Hi Guys

It is now 2 years since I got my 2011 6 Speed Brompton. I have ridden in wet weather a lot. These days I do bike maintenance weekly (clean chain and oil it, plus tyre pressure) however still when I change gear, the change is not sudden, it take it like a second or two, then it changes. My guess is that the cables have had so much dust and dirt in them, that movement is restricted.

So I would like to replace the brakes and gear cables. I have two questions:

1) How hard is it? Are there any instructional videos? Only one I can find was about how to position them (official brompton channel), not how to actually replace them.

2) Can you link me to the ones I need please? I go to SJS Cycles, but there are so many listed that I am worried I might buy the wrong ones

Any help would be greatly appreciated.

Thank You.