Yes, it’s such a shame that this grand tree is being impacted in such an unsightly way.
We live in a small village in Sth Cambridgeshire (moved here in 2003) and there was no infestation at that time. In fact, I don’t think we saw this problem manifest itself until around 2007 at the earliest.
In 2006 we had two examples on the front of our property in close proximity to one another, one of which showed severe decay in the trunk and was leaning precariously over towards our garage. South Cambs Council gave us approval to remove this tree (we are in a tree conservation area), but it’s interesting to note from photos I took at the time that the other tree was in full, unblemished leaf, and this was the end of August!
I wonder if nature will take its course, and eradicate this pest naturally over time.