I noticed this probably 12 months ago, but never posted anything about it on AN as I wasn't certain. Then AN went dark, and I couldn't be bothered registering for on here for ages ..
Anyway, been for a mooch around today on the hillside area above the Halkyn Deep level entrance (the field right next to the A55). There's been a substantial amount of work going on, which has now all being largely landscaped over. Lining up the exit stream on mapping, the main area of work would appear to be pretty much over the line of the level (assuming it's straight for the first portion, which I seem to recall it is, from previous visit to the tunnel itself)
The area of work also appears to be about 800m from the entrance portal - and again, if I recall correctly, the collapse was about that far in (I think UCET did a trip right to the collapse, don't know if Ian or someone could confirm or had any idea as to how far in it was)
Anyway, ATB to you all