Bagworm Update

Following on from my earlier post about a case found at North Dean wood on May 12th and a second on the 17th I'm now quite confident that they are both Narrow Lichen Bagworms (Dahlica triquetrella).
After a fair bit of head scratching and emailing folk I think I can eliminate the main confusion species Diplodoma laichartingella because:

My cases are smaller measuring 8mm x 2.5mm x 2.5mm.
The emergence of one adult mid-April (worked out from the eggs hatching) is about a month earlier than Diplodoma should emerge.
There is no tough inner case surrounded by a lightly woven outer.

The other Dahlica species have smaller cases without a noticeable amount of insect or plant debris attached.
 
There are four records on the Yorkshire database of Triquetrella but I'm sure this is a very under recorded species as it's both tricky to find and identify.
I hope to go back next February to find a couple of pupae to rear.
Below is one of the newly hatched larva just a few hours old and already it had made a tiny case for itself out of fine grit provided.