As Julian points out a CRI can conduct the flight or an FI. The CRI/FI holding a CPL or PPL has no relevance. A CRI who holds an Examiner rating can do both the flight ad the revalidation by experience paperwork at the same time.
As a further option, all LAA FULL coaches are CRI/FI and revalidation Examiners. The LAA website might be able to help you find a coach in your area. LAA coaches are not restricted to permit aircraft.
*The instructor must be authorised in accordance with
JAR-FCL to instruct for the JAR-FCL TMG or SEP(Land)
rating as appropriate. UK QSP only may undertake the
instructional flight with a UK Military instructor. This
training flight may be replaced by any other aeroplane
proficiency check or skill test for an instrument, class or
type rating (as defined by JAR-FCL) with a JAA qualified
Examiner, or by a flight test for the issue/revalidation or
renewal of a UK IMC rating.