Mervyn,
I am afraid that the coin dealer has it wrong. The first piece known as a "Birmingham Sovereign" is an imitation of a regal guinea, these were made in the early 19th century and the legends were changed from the correct ones found on the official issues in order to avoid potential forgery charges. They originally came in tubes of 50 or 100 and were used as gambling chips for card games and the like. The same is true for the model half sovereign, these were issued bearing various dates from the 1840's to 1870's and served the same role as the imitation guinea. The originals of these were issued in about 1841 as commemoratives for the birth of Albert Edward Prince of Wales, again, I suspect they were sold in 50's or 100's but unlike the earlier piece I have never encountered an original tube. As to value, I am afraid virtually nothing.
Hope this is of help,
All the best,
Paul