A quick check on UKcampsites.co.uk using the criteria of seasonal pitches, (this link may work if you copy and paste into your browser http://www.ukcampsite.co.uk/articles/view.asp?id=239 ) brings up these (clickable links on the UKC website take you to the individual site details) :
North West Sites :
Cheshire (View on Map and Add more Search Criteria)
Chester Lakes - Chester , Cheshire
Chester Southerly Camp Site - Chester , Cheshire
Manor Wood Country Caravan Park - Coddington , Cheshire
Pickmere Lake Caravan Park - Knutsford , Cheshire
Royal Vale Caravan Park - Knutsford , Cheshire
Woodlands Park Camp Site - Knutsford , Cheshire
Lamb Cottage Caravan Park - Northwich , Cheshire
New Farm - Winsford , Cheshire
Cotton Arms - Wrenbury , Cheshire
Lancashire (View on Map and Add more Search Criteria)
Clifton Fields (was Gillett Farm) - Blackpool , Lancashire
Eastham Hall Caravan Park - Blackpool , Lancashire
Great Birchwood Country Park - Blackpool , Lancashire
Moss View Caravan Park - Blackpool , Lancashire
Pipers Height Caravan Park - Blackpool , Lancashire
Poulton Plaiz Holiday Park - Blackpool , Lancashire
River Wyre Caravan Park - Blackpool , Lancashire
Windy Harbour Holiday Centre - Blackpool , Lancashire
Bainsbeck Farm Certificated Site - Carnforth , Lancashire
Bay View Holiday Park ( Bolton Holmes ) - Carnforth , Lancashire
Hollins Farm Camp Site - Carnforth , Lancashire
Ireby Green Farm Caravan Site - Carnforth , Lancashire
Morecambe Lodge Caravan Park - Carnforth , Lancashire
Old Hall Caravan Park - Carnforth , Lancashire
Redwell Fisheries Caravan Park - Carnforth , Lancashire
The Villa Caravan Park And Fishery - Carnforth , Lancashire
Three Rivers Woodland Park - Clitheroe , Lancashire
Brocklehead Caravan Park - Darwen , Lancashire
Bridge House Marina & Caravan Park - Garstang , Lancashire
Claylands Park - Garstang , Lancashire
Greaves Farm Caravan And Camping Site - Garstang , Lancashire
North View Caravan Site - Garstang , Lancashire
Lancaster Caravan Park - Lancaster , Lancashire
Moss Wood Caravan Park - Lancaster , Lancashire
Riverside Caravan Park - Lancaster , Lancashire
Wyreside Lakes Fishery - Lancaster , Lancashire
Oaklands Caravan Park - Lytham, Preston , Lancashire
Greendales Caravan Park - Morecambe , Lancashire
Greendales Farm - Morecambe , Lancashire
Riverside Caravan Park - Morecambe , Lancashire
Shorefields Caravan Park - Morecambe , Lancashire
The Sands - Morecambe , Lancashire
Venture Caravan Park - Morecambe , Lancashire
The Moorlands Saddleworth - Oldham , Lancashire
Wellihole Farm Caravan Site - Oldham , Lancashire
Abbey Farm Camp Site - Ormskirk , Lancashire
Shaw Hall Caravan Park ( No Tents ) - Ormskirk , Lancashire
Highgate Barn Caravan Site - Poulton Le Fylde , Lancashire
Beacon Fell View Holiday Park - Preston , Lancashire
Brylea Caravan Park - Preston , Lancashire
Bryning Caravan Park - Preston , Lancashire
Leisure Lakes Caravan Park - Preston , Lancashire
Primrose Bank Caravan Park - Preston , Lancashire
Radcliffe Farm Certificated Site - Preston , Lancashire
Ream Hills Caravan Park - Preston , Lancashire
Royal Umpire Caravan Park - Preston , Lancashire
Holgates Silverdale Caravan Park - Silverdale , Lancashire
Old Manor Farm Certificated Site - Southport , Lancashire