came across tanacetum coccineum bees pink delight at west dean garden center the plant next to it had almost the same name as tanacetum but was spelt different and flower was darker more of a purple any idea of what the correct spelling of this plant is s

That looks like Bees Pink Delight to me. Perhaps the others were paler than they should have been. Can only suggest an internet search against the species. Very often they are grown in such large numbers, micro. prop. method that batches are produced which aren't true to the cultivar name, despite the apparently fail-safe method.

yes that is bees pink but im looking for a plant that almost shares the same name as tanacetum but isnt that name and sorry for the confusion but i have no photo of the plant im trying to id .....if i type anything in to google it just gives me tanacetum ive looked in the index of the rhs big book but not in there ..........there you go

Perhaps a mis-spelling. There are no other plants that I can think of with a name like Tanacetum. There are a fair number of different forms of T. coccineum.