State savings are the highest no risk funds AFAIK. 5 year lock in for longest term. Rates have been slashed in recent years though. Its best you'll get without risk.
Irish Life run funds that people have spoken of on here. MAPs I think they are called. They do all the work, and charge you for same (1% AMC per annum at least)
You could also dump the 25K into a US ETF using online broker. This would be much lower ongoing AMC, but you'd need to do your own tax return, and also pick the ETF(s) yourself.
Finally, could you put the 25K into your pension as a lump sum amount, getting tax relief on the way?