That's a pretty low threshold, but isn't the goal of the tax to make you sell the bungalow so someone can live in it? This seems like a policy working as intended if it's really worth 350k

Due to zoning (not sure how that translates) nobody can live permanently in the bungalow. It is only for recreational use. Has to do with infrastructure, power delivery, sewage, building standards. If it was allowed to live in that bungalow it would be worth double that.