The problem is the one hour review flight and the examiner signature which can only be a UK Flight Examiner.
The UK SEPL revalidation can be done by the UK flight instructor who undertakes the revalidation training flight, but, the flight must complete all of the requirements and the instructor must have the appropriate endorsement to do this.
I would think that it will be easier to find an appropriate UK Flight Instructor locally in the US than an Examiner.