Help please

Whilst walking on Ffos Las on Monday 18th August, I came across this caterpillar walking very fast across the track close to the ponds where the surrounding vegetation is mixed grasses, rushes and trefoils,clovers, tall melilot etc. It was approx 1.5-2"long. I think that it could be the larva of the white ermine moth.  Any suggestions please?

 

Three days later on Thur 21st, I saw my second small copper on site in just over a week, having not seen one since 2011, which was a pleasant surprise.

 

 

There was also this meadow brown with unusual extra pale flashes on the forewings.

 

 

It was a beautiful morning with plenty of butterflies to watch, including a clouded yellow.  A total contrast to this morning (Sat) which was chilly with many fewer butterflies to be seen, but a clouded yellow did put in an appearance to brighten up the morning towards the end of the walk.