we got a set of binatone ones on ebay for £15 posted and they work perfectly.dont get any interference over them sound quality is good and they have a decent range as well
------------- Who needs travel agents,we have our static
we have 2 different sets1 is binatone off Amazon and 1 from an HSS store for building sites cost £20 and £25 respectively. Really easy and our kids have used them since they were 6 with no issues
We have a binatone set and we set them the kids ones to permanantly open line so that we can always hear them. Then they don't need to be able to press any buttons. We also find that mobiles don't always work as the reception on quite a few sites is so patchy.