Natural Fibres - Consider These Brief Points Before Choosing
Perhaps the most sophisticated of the natural fibres and the only one which can be dyed. The most expensive of the three - read about sisal
Harder face surface showing less "loose" fibres than others - read about seagrass
The most well known and reasonable costing - read about coir
When hard wearing floors are necessary and water is an issue, consider the Fenland range from New Way Carpets and Victoria Carpets Natural Collection. Aesthetic appearance very similar to natural (plant) fibres - read about wool alternatives
Short explanation of natural fibres to consider when choosing between coir, sisal and seagrass. All are very popular owing to the rustic appearance that blends particularly well with Cotswold stone and timber. Woven using traditional "boucle", "basketweave" and "herringbone" techniques.
Cautionary note
It's a myth these materials are harder wearing than conventional carpet, honest advice would tell you they're particularly prone to staining. A protective spray called Intec can be applied at additional cost, but it's not a perfect protection and will eventually wear off.
Good advice would be to ensure not to disturb once fitted as re-fitting will almost always lead to deterioration (fraying, stretching etc).