Over-payments when on a Fixed-Rate

Hi All,

I'm currently 9 months into a 3 year fixed rate with AIB. Is it possible to make additional monthly payments when on a fixed rate?

I was planning on making a lump-sum payment at the end of the fixed rate but can also afford to over-pay the mortgage by a few hundred a month at the moment. Would this be worthwhile or should I just continue to save and add it to the lump-sum replayment when the fixed rate ends?

Thanks