For the future...
Any EASA Instructor appropriately rated may do the 'hour with' and if you can't then find a UK CAA examiner to sign the revalidation just send everything to the UK CAA and they'll complete the administrative action required.
Another way around this is for the pilot to "revalidate by test" so the 1 hour with an instructor is replaced by the LPC. In this instance the correct notification process must be adhered to and copied to the correct licensing authority with the completed examiners report post flight. The examiner may then sign the new rating on the front of the licence.
Long winded, but workable.
DD