There's a tiny shoe repair/ key cutting shop on West Green Road at Seven Sisters, if thats not too far for you. It's under the railway bridge, about 100 yards from the Seven Sisters end. I've had shoes repaired that were otherwise write-offs. Also they sharpened secateurs for me for £2. This is the fightback against the ease of just chucking stuff away as you can get new everything for a fiver - including boots.