anyone reconise this plant description? please ?

During the summer holidays we visited the NT Quarry Bank Mill/ Style Country park in Cheshire .once we had gone down all the steps on entering the garden I saw what I thought would be easily identified as a plant from the veronica family.
But I 'm finding it hard and I wondered if anyone also visited and can recall seeing and knowing what it was .I know it's a long shot. But other than this I shall send them an email as its bugging me AND I want some of these seeds
Right here goes : wish me luck .....I'm not so good at describing .
It was about 4 ft tall , sparsely branching out from the main slender stem was leaves in bit of a cluster then coming from them maybe another 3 stems . At the end of each stem was a purple flower. The flower was as a veronica in style and must have been about 4-5 inches long. At the top of the main stem was the flower too. Some other visitor commented that the leaves were reminding her of cannabis but never having grown cannabis myself I can't think what she meant!
I took some photos but can't find them at moment
Posts
Have you looked at Veronicastrum Gran?
In the sticks near Peterborough
beat me to it Nutcutlet.
In the sticks near Peterborough
While reading the question I was going to say Veronicastrum, but I'm beaten to it as well!
WOW !!!!!

A Smiley face and a big thank you to you all, Nut ,Hostafan1 and for the impressive spot on picture from Busy-Lizzie..
This is what it is ,and now I can visualize in our garden next year,getting all excited just thinking about it
Many Thanks again
Gran x
verdun re cannabis
I'll try anything once!
You would probably try it twice Gran!
That is a beautiful plant, would it grow from seed, does anyone have any please!
I am always on the lookout for something to fill a big space.
Of course, I wouldn't know what cannabis looks like
In the sticks near Peterborough
Hmmmm
Lyn do you mean the cannabis is a beautiful plant and you wouldn't mind trying some ?
Put me down to try some too , let's sample it together,could help get us through the day 
AND night
...................