Hello rjbevan,

Take a look at the article published on the global property guide web site on rental yields which I think you will find useful in deciding where to invest. The article is titled: "London and Monaco are Europe’s most expensive cities for residential property buyers" (I am not allowed to post a link).

It ranks many european cities for capital cost & rental yield, and indicates that eastern european countries have low priced property capable of producing a good yield. The article is a little out of date but indicates yields of 10% or more are realistic in the right location.