Toby......
Again, since you are in the UK, I don't know if this product is available...but.. I've found that "303 Aerospace Protectant" is the best for cleaning and protecting vinyl. It will clean and protect vinyl and rubber without harming it and
give it a luster. It contains no silicone, petroleum products, etc. which most other vinyl cleaners do and while they will make vinyl look good they will contribute to it's breakdown. 303
also has a UV filter.
Biff