Funny you mentioned that site as my brother actually bought some to try out on his L200 leather seats that had a long tear in the drivers seat and they came up bloody good. Think of it as super glue for leather lol. He did it over 6 months ago and still no sign of wear on that area.
If it helps he bought the Professional Leather & Vinyl Repair Kit - Instant repair (no waiting) kit
Haven't tried it myself though as my seats (touch wood) are ok atm lol, and I would most defo give that stuff a try if I needed it.