Hello All - thanks for reading.

I bought a Tag Heuer from this very forum a while ago. It was cheap as it had a known problem. I took a hit and gave this to my watch repair man. He advised that the movement was replaced. I agreed and paid £140 for this.
I have been wearing the watch daily for a while and have noticed that the top button makes one of the chrono dials spin a bit and the red seconds hand ticks around.
The bottom button appears to do nothing.

I took it back to him and he unscrewed the crown and tried again and all the dials seemed to spin a reset.

How should this watch work? How can i test it is working as it should as i am debating selling this and want to ensure that the new owner is happy.

Many thanks