Pic below is pretty self explanatory.
Material used: Old inner tube cut to size and a velcro (could have just use another ring cut of inner tube but I was too lazy to pull out the post to loop it through)
While it won't win any award from the Ministry of Aesthetics but everything is neatly wrapped up without any ugly bulging. Its very possible to modify the design here slightly with a groove in future generation of this post to accept a piece of soft plastic to cover up the cavity...
Raining everywhere on the island now... no better time to test out this DIY.
Sun 8 Jan
Not muddy but pretty wet. Enough grit and sand was sprayed up to the seatpost. Everything looks good and well protected. No irritating bits getting in and grinding with movable parts within the cavity housing the actuation pin.