This is what the RHS say about it- Monarda 'Beauty of Cobham' is a clump-forming herbaceous perennial to 90cm in height, with aromatic, lance-shaped, purplish-green leaves. Terminal whorls of two-lipped, pale purplish-pink flowers 5cm in length have contrasting purple calyxes
Colour
Flower
Pink and Pale Purple in Autumn and Summer
Foliage
Green and Purple in Autumn, Spring and Summer
Size
Ultimate height
0.5-1 metres
Ultimate spread
0.1-0.5 metres
Time to ultimate height
2-5 years

Thank you DCR726 .It always makes me chuckle at the difference in heights listed by each nursery and even the plant labels but I would hope the RHS know their stuff although i've been waiting four years for my Astrantia Major to make the height they state .I know that growing condition and light levels alter so much though :-)
I shall assume its a cool pinky purple and site accordingly. I always like to see things normally but these were a bargain.Many thanks for your reply :-)

Your welcome

I shold have photos of it from last year. go to 'my page' and then my 'garden' section. it is listed under the monardas. it got to about 2-2.5 ft tall.

Thank you Seaburn girl :-)