Solved Sure I have asked what this is before but forgotten again!

Apologies but have forgotten what the below is. It sort of looks like a Euphorbia but I may well be wrong. I got it years ago at an open garden. It is very slow to bulk up here. Grows about 2ft tall maybe and flowering now. Definitely not the star of the show and it will be offered for sale at my next sale I do for charity. Would be good to know what it actually is. The photos are a good match for the colour of flower which is a wishy washy fawn no scent, not interesting shape or colour of foliage so in other words not a lot going for it really.Thanks in advance.

 

Wondering if @Silver surfer will come to my rescue? Their knowledge of plants is encyclopedic

 

Bupleurum longifolium

 

Oh many thanks @Palustris and @Marley Farley. Spot on and Jee I have never even heard of the plant. Maybe I hadn't asked before what it is. Wow is it slow to bulk up. I have had it for about 10 years and apart from giving about a 1/4 of what I had to a friend who liked it the clump I have will only be about 1ft square at most. Do you use it in dried flower arranging? I am not bad at growing plants but trying to make what I grow look good in a vase or whatever is not my forte I am afraid.

 

Never made a big clump here, but it does spread from seed very easily.