I'm not sure if they do. Just out of interest though here are their prices:
Flsmingoland: £100 LWV: £60 Paulton's Park:£87.50 Thorpe Park: £85 Alton Towers: £90 Chessington: £79.92 Pleasure Beach Blackpool: £189.90 (2012 season, not 12 months. What is already wildly extortionate becomes more and more so as the season grows old, from what I can see.)
Judging by this list PWH doesn't seem too bad but I still feel it is overpriced. LWV's pass us very reasonable and the Merlin parks passes' value are bolstered by the perks. I think PWH would sell more passes at its current price if they had perks. Posters around the park saying get 20% off your food/gift shop with our season pass. Or get you entry refunded if you buy a season pass today. Or half price karts, laser and Zorbs with our awesome season pass. There's so much that could be a massive win with these. It seems like Merlin are the only parks with additional benefits on the passes.
Problem is though that Merlin can offer these perks as they have an (almost) monopoly on the industry
a Premium MAP is £172.80 and a Standard is £140.40 - with family ones at £129.60pp and £105.30pp
So if you pay £172 a year for a Premium Merlin Pass you get unrestricted entry to any of their attractions (Alton, Thorpe, Chessie, Legoland, Blackpool Tower, Sea-Life, London Eye, Madame Tussauds, Dungeons and Warwick Castle), free parking, and 20% off all food, drink, merch and hotel stays... The fact that they own so much puts everyone else's season tickets as bad value for money really (apart from maybe LWV).
I think what Josh said is spot on about the posters around the park. I bet if you asked all the guests in the park, none of them would probably even know they done a season pass, so getting the point across with those posters would well. Especially the 'Entrance fee refunded' and maybe '20% off food' outside the restaurant! ;)
