I would also like to use the property for a health retreat as an extension of our UK business, so would like somewhere peaceful, in a country setting ideally.
Househunt take a look at Wysowa in the Beskid Niski region, just 2 hours by car from Krakow. Visited there last year just for a day, it's a nice spa town close to the slovak border. attracts many tourists and the house prices haven't spirald out of control yet.Your budget will still go a long way there.
pl-info.net/poland/health-spas/wysowa.html