A thing which lives in our database and has an id.parliament.uk URI which has a counterpoint on Wikidata. Not necessarily something which is orchestrated from Wikidata, which the [Source]Thing class name tends to indicate in our schema. A more unwieldy name might be ':WikidataEquivalentHavingThing'. Hopefully this comment ameliorates the slight inconsistency
:WikidataThing no website description provided