Locations in Colombo or Wast/South coast?

My wife and I are an English couple relocating from Dubai to Sri Lanka where we plan to spend a few years of what we call our ‘2nd Childhood’, we both dislike the term retirement! We arrive in Colombo on Friday 10th June and have an apartment for a month while we decide where we wish to live long term either in unfurnished rental or purchase property.
Our current ‘search area’ is too broad encompassing Colombo down the west coast and on past Galle to the South coast so we would appreciate any advice you can offer on where we might focus our attention? We want to be able to take advantage of Sri Lanka’s beautiful sea and also contribute by doing some animal charity work.