ST-200 Supertweeter placement with Tannoy Kensington

I recently obtained a pair of Tannoy ST-200 super-tweeters  - they were included when I bought used pair of Kensington SE speakers.  The super-tweeters come with a gauge showing how far from the front of the cabinet they should be placed for a number of models of Tannoy speakers.  But the super-tweeter documentation must have been written before the Kensington SE came to market because that speaker and anything later do not appear on the list.

I sent a request through the Tannoy web site asking for advice on placement of the super-tweeter and got a reply just now.  It was a picture showing that they should be placed on top of the speaker!

If there is anyone who can offer more useful advice than this, it would be much appreciated.