The headset requirements for the R22 can get difficult, as certainly when using Peltors you have to have a special version with a bridge rectifier in it.
I would tell the supplier that you want to use them with an R22 and let them tell you which version you need. That way when they don't work as may well be the case, it is down to them to sort it out for you.
You will also need to tell them whether you need a UK Nato (bronze) or US Nato (silver) plug. Just look at the existing one to determine this.
I speak from experience!