Possibly need lifting and splitting and some humus rich compost dug into where they are going to go. Eventually an clump of bulbs/corms/rizomes gets so tightly packed that the individual 'bulbs' can't get enough nourishment.

Thank you very much, I will give it a go.

my thoughts were also on the congested side. remember only the corm nearest the surface will flower so you can get rid of all the others.

Thanks Seaburn girl appreciated advice

Never give up with Crocosmias. They don't like very dry conditions and heavy soil, and we brought some with us from the UK when we moved here ten years ago. We planted them in various places and there was hardly any evidence of even their leaves for around five years. Then suddenly, after a lot more rain and a reasonable summer they all burst into life.
I've noticed the leaves are again growing well with all the moisture this year, so we are hopeful we may get some more flowers after two or so flowerless years. I think they don't like very dry ground. Their natural habitat is in boggy ground and alongside streams.