Hi, Sumo, it would help if you could give the plant a name.
However, without a name and going on my own experience, I would suggest that this plant does not like exposure to full, hot sun (eg some saxifrages) and that the dry side is facing south. I would consider moving it to a position with plenty of light but where it won't get burnt.

A description of the plant or, even better, a photo, will help us give you a clearer answer Sumo.

Hello Bulbaholic and Moon grower, apologies, not the worlds best gardener.... the plant has been in place for about 2 years now (so I can't remember the name) the 'strands' have grown to about 8-10 inches in length, some of the strands have small green/white leaves and blue flowers but other strands still have some flowers but appear to be dried and dead. The bed is east facing and gets the best of the sun for hottests part of the day. Sounds like I need to move it, but when it was a smaller plant there were no problems. Sould they ever be cut back to encourage new growth?

Hello Sumo, your description is now sounding like Aubritia which should be able to withstand British sunshine. Is it exposed to cold, winter wind on the side that is dry and straggly? Moving to a more sheltered location cvould help.