Work in Ireland but company registered in UK

I work for a company who has an office in Ireland, employs 10 people but whose registered office is in the UK. No-one in the office has received a contract of employment and rarely do we receive payslips. We are paid monthly directly into our accounts. In addition we work very long hours and are told we must work the hours that the job entails. On average this is 12-13 hrs per day plus we are "on-call" (which is often and mostly in the evenings and sometimes weekends). We are unsure if the boss knows that there is a maximum 48 hour working week and that he is breaking all employment rights by not offering employment contracts etc.

We have been told that we are subject to UK employment rights. On the latter I know that we are subject to Irish employment rights because we work in Ireland. However the boss does not want us to take public holidays and can therefore control when we take our holidays under UK law.

I know I should report this man and his business to NERA however, in the past, the boss has threatened that he will just close the Irish operation and move to the UK.

Any suggestions on how to deal or resolve this situation are most welcome.

I understand that this is a tough one, but you have to look at the overall business and try to determine if it is a successful one which your "boss" wants to continue with.
If the business overall is turning a healthy profit, then his threats may be just that, threats. If the profit is sufficient, he won't want to close the Irish operation. I would suggest that if he has kept 10 people employed through the last 3yrs, then it is a business he wants to keep going.
I would recommend that you - as a group - stand up to your boss and threaten to go to NERA. However, I would recommend that you look deeper in to how your salaries etc are being handled, especially payments his company should be making to the Revenue, as it is possible that he is "avoiding" some of this in the manner he has chosen to work.

Indeed this is a very tough one. You and your colleagues need the work but you are also entitled to be treated fairly for the work you give. Flexibility required by a employeer is understandable also; if for example the main source of business is located in a particular timezone or country, employers can reasonably define that to meet the market needs the terms of the job require working days or hours different to the standard local holidays; you must however be compensated for that and you must have a contract whcih defines your obligations.
If no one has a contract then this is a serious issue, you are entitled to that especially so even in UK law. If the employer is not facing up to those obligations then what else is he not in compliance? If you are not geting payslips are you sure your contributions are being paid - you should check as a group.
Get some citizens advice (try bodies here and in the UK) so you are covered and then approach the employer with a solution proposal to resolve your collective problem. The previous poster made a vaild point in that if you are still employed after the last three years, the business must be valuable to the employer so he will play ball. Lets face it sometimes people can be bullies and when bullies are faced down they usuallly give in.
So approach with caution, get your fact straight and put in place an action plan. Some of the solution you may not love but at least it will be better than not knowing. If you dont like the clear terms of employment then you may have a choice to do something about it, at your own time of choosing.