I would to spend about 4-5 weeks meditating in a remote, simple cottage somewhere
in the Canaries. Here are my criteria:
Not within 100m of nearest house, but within 3 hours walk of food
supplies (or some other public transport)
Rural location or outskirts of village
I will be on my own, so only needs to house one.
Electricity preferable, and available water.
In a mountainous region within view of the sea
Cost up to 400 euros per week (pref less)
I suspect that La Gomera or El Hierro is more likely than the more
developed islands, but I'm open-minded provided the criteria are hit.

Can you give me any phone numbers or websites of likely places? I've
looked for "self-catering la gomera" and suchlike, but it usually
throws up villas or fancy expensive places.

an absolutely ideal option would be to stay in a solitary hut of a
retreat centre (even more ideally a Buddhist one).

We have a beautiful property that may work for you.  The
http://www.vacationrentalsbyweb.com/post_html/1697_post.sht is the
page of this villa.  Go check it out.

rentprez@vacationrentalsbyweb.com

You can find some remote, rural cottages in the interior of the
Islands, quite small and cheap too. You can usually negotiate cheaper
for longer stays on
www.coloursofspain.com If you can't see what you exactly want you can
also ask them to find something. La Palma is the best small Island
too.