I don't imagine it's unusual. Admiral were brilliant when a lady drove into me and admitted 100% responsibility. I think the issue comes down to when there's not much evidence against another party, the other insurance company is going to drag things out and try their hardest to not have to fork out for the repairs. The admiral guy on the phone said the other drivers insurance company was known for dragging things out and "not receiving letters" etc.
At least now I'm getting updated a bit more as it's been passed to Admirals solitors to "begin proceedings"
or the other insurance company is admiral themselves.