The CAA quote comes from an old derogation which appeared in CAP804 shortly before EASA changed from the old 'single flight of at least an hour' to 'cumulative total of an hour's refresher flying'. This followed lobbying by IAOPA (Europe).
I don't believe that the CAA's more restrictive '3 flights max, all with the same instructor' still applies - if it does, it would be blatant auric embellishment*!
*They hate the term 'gold plating'!