Another large beetle arrived in the moth trap last night, Geotrupes stercorarius, commonly known as a Dor Beetle. There are 29 previous records of this species from Glamorgan (in Mapmate). The only other one I have seen was funnily enough on the 6th of October 2012.
Like many beetles they often infested with small troops of mites. I'm not sure if these are parasitic or harmless. If anyone knows do please tell me!