muraria:
Where there is just one anagram,you can enter it in Grid 2.
Where there are two, you pick one and if that works, fine. Otherwise use the second one.
I just did a few.
The unchecked letters in down clues remain same.
So 21a, 29a, 34a and 38a anagrams you can be reasonably sure of.
By keeping the unchecked same, I get 19d as Cork and 17d as a German coin.
I hope I am right.
More in 30 minutes.