Water will indeed pass right through as long as you give it room to do
so. I was thinking of pebbles or stones deflecting it off and into the
surrounding grass. Putting a length of pipe or your cut off bottle
into the ground and watering through that is a really good solution and
is something used a good deal in places where water is in short supply.
When I lived in Jersey, many jobbing gardeners were Portuguese from
Madeira and they employed that method quite often.

OK - understood. I'll give that a go. How deep should I bury the pipe /
bottle ??