Hello Tmpleno,
Welcome to the Community page,
As far as I'm aware the only way to cancel a desktop account is to ring the support line and they will cancel the account on your behalf. The steps you were trying for canceling the account are more likely the steps for the US product, not the UK on.
If you ring the support line on 0808 168 9535 they will be able to cancel your desktop account there for you.