Yes thanks Opimax and Robh.
I changed the connections to the drivers according to the resistance through the crossovers but that was not conclusive as the resistance was almost exactly the same. Only changed one speaker and left the other as it was. Actually they sound almost identical - with the modified crossover sounding less boomy.
I think the only way to be sure is to test the speakers with a sound level meter. Can anyone recommend a decent setup to do this?