British Recycled Plastic's Hebden 402 ecopaving is widely used as a ground reinforcement grid, most often as driveways and carparks due to its strength, but the other day I took a look at its use in a sloping garden.
The owner was looking for an ultra-low-maintenance pathway that would make it hard for weeds to take root and thereby start to seed the raised beds.
Tarmac wasn't an option due to the combined issues of lack of access, Council planning regulations, cost, and poor aesthetics.
Block paving was ruled out due to prohibitive expense and straightforward gravel chippings couldn't be used because the garden is sloped and they would eventually have all migrated to the lowest point.
If you're interested in how it was done and what advice the owner would give to anyone else thinking of doing the same thing, you can see a video interview here, or you can download a pdf of the case study here.