Red Admirals
I have found them what i thought was hibernating in the school bolierhouse in sept. only trouble is when the boilers kick in in Oct it wakes them up and they seem to die,more info below from google.
The Red Admiral is a frequent visitor to gardens throughout the British Isles and one of our most well-known butterflies. This butterfly is unmistakable, with the velvety black wings intersected by striking red bands.
This butterfly is primarily a migrant to our shores, although sightings of individuals and immature stages in the first few months of the year, especially in the south of England, mean that this butterfly is now considered resident. This resident population is considered to only be a small fraction of the population seen in the British Isles, which gets topped up every year with migrants arriving in May and June that originate in central Europe. Unfortunately, most individuals are unable to survive our winter, especially in the cooler regions of the British Isles.
The number of adults seen in any one year is therefore dependent on the number of migrants reaching the British Isles and numbers fluctuate as a result. In some years this butterfly can be widespread and common, in others rather local and scarce. This is a widespread species and can be found anywhere in the British Isles, including Orkney and Shetland.