Further to my comment to Douglas, I do not actually own this type 2 pack, my scan was taken from another pack: (amended) Cathedrals which also has the 2 types of unicorn head.
However after doing some research I have only found one other pack (26) listed. This is the Scandinavian pack 26 , which was, quote "A special pack produced for sale during a visit to six cities in Denmark, Sweden and Norway by a mobile display unit between 15th April and 20th May 1971. The pack gives details of this tour and also lists the the stamps which were due to be issued in 1971, the text being in English. A separate insert gives translations in Danish, Swedish and Norwegian. The pack was also available at the Philatelic Bureau, Edinburgh."
The Scandinavian Pack is catalogued at £30.00. Normal pack : £5.00
Sorry Douglas I am still no wiser to answer your question "Are there two types of English packs?" It certainly looks that way. Pehaps someone else could enlighten us further?