Tickets are on sale now and are limited availablity. Price has gone up to a tenner plus a £1.13p booking fee per ticket. https://www.tattonparkvwshow.com/tix/
I think the prices have gone up as they're not allowed the full capacity of a normal previous year but still have to pay the full whack for the use of Tatton Park. They barely make much of a profit normally so it may run at a loss this year.
Still 2 places left. Tickets are selling fast from the sound of it and once they're gone theres no 'pay on the gate' entries.