To answer what I see as the actual question...
Suppose the ticket costs €1000. This must be paid for with a salary sacrifice, therefore it reduces your taxable income by €1000, so another €1000 of your income will come within your existing tax credits. If at least €1000 of your salary is currently taxed at 41%, you will benefit from full relief on the ticket. You may need to ring Revenue to assign more of your excess tax credits / tax free allowance to your second employment (or alternatively get a tax refund at year end). If you earn more than €50,700 a year (doesn't apply to you, but could for others), you may not get the full PRSI benefit.