WOLF'S CHEMICALS TYRE & TRIM GEL (BLACK OUT)
Never used, but seems cheap enough to try. Is there a reason you must order off that site? I'm sure you have detailers in the UK right? Ask around and find out where the detailers get their professional grade supplies at and go there. It should cost around $20-25 US per gallon for a good tire dressing. That should last you a year.