@divine1966 thanks again for your input on these forums. I find social, friendly, polite often gets interpreted as interest also. Your post reminds me that it's important to say out loud, "I am not interested in having another date". Ack, so simple and I don't know what blocks me from communicating correctly! Note to self once again.
I guess actually what stops me is that once all the hormones and love stuff start flowing I become ambivalent even when I know that I am not interested.
There is also ambivalence if we have common interests so I might want to carry on a friendship in future but not a date.

I have a load of work to do on friendships, relationships, boundaries and such yes/ no communication issues. Ack, and double ack, but thanks for the useful pointers .