There is only one place you should be giving your personal information to apply for your ESTA, and that is U.S. Customs & Border Protection.
Every UK person who wants to visit Walt Disney World (or anywhere in America) needs to apply for the ESTA (unless you have a VISA) to gain entry into the U.S.A. Back in the day, you used to fill out a white form on the plane, but now it's all done in advance electronically. You will not be allowed into the country if you arrive without completing an ESTA.
Since this change, third party websites have cropped up offering confused travellers help while charging hefty fees.
Completing an ESTA can be a little daunting, but you will be charged extra fees and the U.S. Customs & Border Protection will not grant you entry if the third party company does not submit the ESTA correctly. So please, just apply for your ESTA with U.S. Customs & Border Protection directly.
If you are on a website that charges you more than $14 to file an ESTA then stop. You're likely not on the official ESTA website. These third party websites charge you hefty fees, are not held responsible if they don't do it correctly, and you don't know what they're doing with your sensitive personal data.