I've just run a search under 'Explore All Records' for Pyrrhidium sanguineum and it returns a lot of erroneous results, including other longhorn beetles, bugs and a wasp. It seems that the filter is picking up any records labelled with the common name 'Longhorn Beetle' rather than restricting the search to the scientific name only.
The second question is why has Pyrrhidium sanguineum been given the common name 'Longhorn Beetle', when this should refer to the whole of the Cerambycidae? It's an extremely bad and confusing name choice. An alternative name in use is 'Welsh Oak Longhorn Beetle', which at least has the advantage of being unique although it doesn't seem very appropriate for a species distributed across three continents. Even within the UK it seems misleading for a species that is becoming more widespread in England.