Hello Marion. Here is a fab link for you as it grades the height, scent and colour of all the lavender's. Make a note of the names and then google a pic.

http://www.goodwincreekgardens.com/advice/AdviceLavenders.asp

Thanks ever so much Pimpernel, its a great link and very informative, at the moment I am researching the Hidcote Giant I found on there.