If the contractors are outside the Irish state , you are in trouble. Within and you are covered by employment law.
1. Does this fall under TUPE legislation ?
Ans: have company offered you new contracts ??, TUPE is changeover of employers in the main, and the existing contracts remaining intact (pensions excluded)
2. If roles are replaced by outsourced staff, am i right in thinking this is not redundancy as defined under Irish Law ?
Has the company treated to sack you, and directly replace you with contractors.
3. If the employer claims that the change is due to 'organizational restructure' is employee legal protection pretty lame ? Surely all employers can always do outsourcing by claiming 'organizational restructure' ?
Oganisational restrucure is usually a byword for reduction of staff, but direct replacement with staff on lowere T and Cs is technically unsound in LRC / Labour Courts.
4. How would an employee know that their dismissal was solely due to outsourcing (and so is not classed as a redundancy, and is better protected under law) ?
If role was direct replacement, no issues with skillsets ... only reasoning was cost ... have a good case in Tribunal.
http://www.citizensinformation.ie/en/employment/enforcement_and_redress/
Check the Free Legal Advice, look for Industrial relations specialist ..
When you have more info, feel free to post , if necessary
http://www.flac.ie