HB999
I think that's a very reasonable request for advice under these abnormal circumstances and am surprised there haven't been more.
I'm actually on the other side of the world so I'm only reading about what is going on in Europe. My advice would be to exercise greater than normal caution in making that decision to fly. Obviously, if a restriction is placed on vfr flight in UK then the decision is taken away from you, but even lacking any flight restriction, if there is ash or thicker than normal dust settling on your car, I would have to consider what it would do to the air filter whilst airborne, or to the blades as you mentioned.
There seems to be some disgruntlement and disbelief at the caution being displayed by those in authority, maybe it is overkill, I don't know, however, sometimes we just have to accept that those decisions are made by fairly smart guys, being paid to make wise decisions for the benefit of most people.
You might ask your senior pilot for his advice, get some top cover. Or ask the person who is liable to pay for the repairs if any damage is caused.
These are abnormal conditions, it's a very reasonable cause for some concern.
Have a good flight......or not.
Tam