The United Kingdom domestic market (UKDM) is the United Kingdom's market for purchasing things, chiefly automobiles. A parallel concept, the JDM differentiates Japan-only products. This also pertains to the parts and products only available within the specific local marketplace. Therefore, unless you are in the United Kingdom, parts have to be specifically imported to your target nation. There are a variety of importers that bring in these parts into other marketplaces.
References
United Kingdom domestic market Wikipedia(Text) CC BY-SA