I had another go, this time I only used SESSION and it worked. The coding is not exactly as above, now all SESSIONS are at the top.

It seems illogical. You have to create SESSIONS at the begining of the page but it is taking variables from further on. I always thought that the script was read in a continous sequence from begining to end.
Another odd thing is that I have PHP - HTML - PHP scripts. PHP Variables can be manipulated across HTML code, it does not have to be one continous PHP script.

Now I have another problem to solve. The only way to reset the score is to close the browser. This might not even work in Opera as it Caches everthing. I thought that by going to another page the SESSION would terminate. I will have to add a "Reset" button.

Tony