I had a peek at the website given. These are tours to foreign lands...Morocco, Guernsey, Ireland, Norway, Scotland, St Petersburg, etc... Pippa Greenwood is leading one tour, and 3 other gardeners who have appeared occasionally on telly, are leading other tours.
I believe that last year, Alan Titchmarsh led one of these cruises, organised by the same company...
Disappointing that Monty isn't taking a group around the gardens of France or Italy. I always thought that would have been a great idea.
Many of the tours depart from Southampton. There are some attractive gardens in Southampton. We know of at least one. Not sure if that one is on any of the itineries.