A German Iron Cross medal
Around 218,000 of these were awarded to Germans in the First World War. The W stands for Kaiser Wilhelm. It is a pin-on medal with no ribbon and was worn centred on a uniform breast pocket, either on dress uniforms or everyday outfit. It was a progressive award, with the second class having to be earned before the first class and so on for the higher degrees.
We do not know who this Iron Cross was awarded to or why it is in Yeovil.