Solution to boggy clay path?

I watched DIY sos the other night,the one where Chris Beardshaws chelsea garden was transplanted onto the roof at GOSH. They used some sort of underlay,for want of a better word,that looked like rows of black toblerone,covered it with shingle and put pavers on it.
I have a boggy area in my allotment that is getting worse with each visit as we walk on it.
Can anyone tell me what they used and if it would work if i dug out the clay,put some of this underlay thingy in then stones and finally replace the paving stones which i took up to put woodchip down.
Many thanks.
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https://www.ebay.co.uk/itm/12-x-Gravel-Grass-Grid-Paver-Base-Greenhouse-Deck-Path-Turf-Lawn-Shed-Garden/153894421908?hash=item23d4d28594:g:6JgAAOSwoexfmKgq&var=453948695064
I think you have to do a bit of prep before laying it, but I don't know how involved it is. Maybe a layer of hardcore and landscape fabric first.
We're on heavy clay, and it's permanently wet. When I make paths, I just lay thick l'scape fabric and a good layer of gravel. It's always worked well.
Just a bit of hardcore and gravel with timber edging, or just gravel on landscape fabric... or even bark. Fairly cheap and easy to keep topped up. Don't use round gravel like pea shingle, use something angular.
We have areas of our allotment which regularly flood in Winter. All of our paths are covered in a weed suppressing membrane, and then covered in bark chips. The membrane keeps our feet away from any muddy soil, and to some extent the bark chips soak up smaller amounts of heavy rain. Although membrane is nasty stuff for the environment, it might be a better solution for you than the plastic grid you mention. You will need to cover it in bark chips, or something else. To give you an idea of just how wet our plot gets in Winter...
The muddy clay though is out of sight, thanks to the membrane.
All I can say is that I used it to make a path up my lawn during the Somerset floods in 2013 and didn't drown when walking to get to my GH
I also used it in a similar fashion to @KeenOnGreen - in my case for the GH base and filled with gravel. Worked well in that situation.
Five years later the slabs have sunk to just above the surrounding ground and, surprise bonus, the excess sand has worked into the surrounding soil so it dries faster. The path is bordered by raised beds, and I think without these the sand may have just emigrated.