I used "Mer" Bumper and Vinyl Cleaning Gel. It is fantastic, restores the colour, and makes it waterproof. Bit of elbow grease and time required but it's well worth it. £4.99 plus postage on Fleabay.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.