If it is only 3 diopters of esophoria there is nothing to worry about.
Your freind that had surgery did not have the same condition as yours.
The only thing is your prescription is a bit high but that will not be a problem for FAA medical and I don't think for JAA. I strongly recommend that you take an FAA medical exam in France and a JAA medical in the UK.
If I where you I would not worry so much about the medical instead I would worry much more about the following.
1) How are you going to finance your training without getting bankrupt.
2) How are you going to get a job.
Just to give you a taste. I graduated in 1998 with an ATPL and I have about 1600 hours of that 500 hours Multi-engine PIC.
Since then I have sent out about 2000 CV's (no kidding) and got only one interview. All my savings goes to flying and books in order to keep current and up to date.
I am 30 years old and I would really like to start a family but I need to wait for that job to come.....If I ever will get one.
Ín the situation I am right now I am not even able to have a girlfreind.
Last time I got laid was 4 years ago
If you ask me if I regret that I became a pilot the answere is....YES but it is vey hard to accept the fact that I may never get that job. All the money and effort I have put down on this, it is vey hard to just throw it away and say that I will do something else.
I would rather be a medical doctor and keep flying as a hobby.
These two problems are far more serious than your 3 diopters of esophoria or the lack of seeing stereoscopic images.