Do I owe US tax on UK wages over a certain amount?

I think I've worked out that if my UK income less deductions ($6,300 standard) less exemption ($4,000 for me) is greater than the maximum foreign earned income exclusion ($100,800), I will owe the IRS tax on this excess.
Have I done something wrong?  This seems like double-taxation to me.  The tax paid in the UK is definitely greater than the tax that would have paid in the US.
From other threads, it seems I should go to britishamericantax.com, but just wondered if anyone had experience / initial thoughts in this area, before I go there.
Thanks.

No, it is unlikely you will owe any tax to the IRS. The UK tax you have paid can be used to offset US tax liability by claiming foreign tax credits via forms 1116.

When choosing a tax preparer/advisor one thing to consider is their accessibility and responsiveness. Some will respond rapidly by phone, or meet with you for a face to face interview. Others may take weeks to reply to an email, or may never reply at all. It is probably worth obtaining two quotes for your work. From personal experience I would recommend americantaxreturns.com.