John Burke wrote:

By the time I fetched my camera it'd gone.

It stayed on the ground for a few minutes and displayed speckled orange
wings.

Can anyone identify it?

Likeliest thing is a Speckled Wood butterfly. It is usually a woodland
butterfly but it does occur in gardens.

The caterpillars eat grasses.
Here is a picture.

http://www.butterfly-conservation.or...kled_wood.html

Neil Jones
http://www.butterflyguy.com/