You are correct that having reimbursed yourself for the insurance premiums from your pre-tax HRA, you cannot also deduct these expenses on Schedule A.
"HRAs are funded solely through employer contributions and may not be funded through employee salary deferrals under a cafeteria plan. These contributions aren’t included in the employee's income. You don’t pay federal income taxes or employment taxes on amounts your employer contributes to the HRA." Page 17 of IRS Pub 969".
