Finally made the decision about the fireplace...We have bought a cast iron inset with pine surround from Ebay!! (wonderful Ebay!) It is from the period circa 1800, and is supposed to have originally come from Kildale Hall in North Yorks, (although not sure of provenance of item).
It has previously been used for solid fuel, and comes with grate and fire front, but however doest need some restoration work to cream tiles and to metalwork.
We decided that better to install something with "character" into the cottage, rather than a new bright shiny fireplace....more pics to follow once it has been delivered!