Holyhead's quite far from any urban centre and flights are generally cheap enough now that most women just fly. As I understand it they are expected to stay for at least one night (possibly longer if they are having a medical abortion, although those are not usually available except to women who are already registered with a British GP).
There are organisations that will provide assistance to these women on a not-for-profit basis but I've never heard of anyone trying to set up an actual 'industry' to bring them over - if the law didn't shut it down (and quite possibly it could), the public outcry would.