Plenty of attractions of different types operate free (admission included) timed ticket slots on a first-come-first-served basis, so let's not pretend that charging £10 per maze was Thorpe's only option here.
I understand that the parks have suffered a lot financially this year, but nevertheless I don't think it's right that Thorpe have introduced such a hefty fee for these mazes when they are essentially one that has been around for years and Blair Witch without the IP. Ultimately I do not believe it represents good value for money and it feels as though Thorpe are exploiting the fact that they are one of few operating Halloween events this year by charging such a high amount.