If I play Dwarf card Grudge Thrower Assault 'destroy one target attacking unit' and target the Orc Lobber Crew can the Lobber Crew still use its action and say that it is sacrificed, not destroyed and make me sacrifice a unit or does the Grudge Thrower Assault action resolve first? thanks

Not normally, because the Lobber Crew's ability only works in the Kingdom and I can't think of an effect that would let it attack from there.

Ok, let's assume there's some magical effect that doesn't exist yet that would let the Crew attack from the Kingdom. In that case, yes, they could respond to you destroying the Crew by using its sacrifice ability.

2 things to note there. (1) actions resolve last-in-first-out, so the Crew's ability resolves first. (2) removing the source of the effect does not cancel the effect (or Lobber Crew would never do anything when you sacrificed it).

ahhh, thanks I didn't spot the Lobber's action can only be used in the Kingdom zone, I shall tell my husband off for trying to use it while he was in the battlefied!