On John's recommendation I went off to see the purple heron at Ynys-hir in the gathering gloom this evening. By the time I got there it was being very active (for a heron), it turned round twice, peered at the water, had a neck stretch and then flew towards Ynys Eidiol hide before diving out of sight into the reeds to the right of the hide. Photos for record purposes - if you half close your eyes you may be able to make out a heron.