As soon as you click on the orange button on the sign-up page you are agreeing to the £30 professional selling plan - you need to read the small print under the button !! (£25.00 +VAT).

So you do not pay any more until your account is fully verified you can downgrade the selling PLAN (NOT account type) to individual by going to Account info - manage your services - and clicking on the individual button. They need to take a small amount to verify your bank details, but it is not actually taken (or possibly refunded - I can't remember the exact process).