Royal Umpire Touring park is not that far from wigan. Its located on the A581 Chorley to Southport road at Croston, 6 miles from J27 and 4 miles from J28 M6. Its a private park but Im told its quite good but I havn't visted it.
Web site is www.royalumpire.co.uk
Tel 01772 600257
Hope that helps
Brian