Vintage automatic Omega watch Seamaster day-date stainless steel new price 400 Eur

Hi

I have for sale a vintage Omega Seamaster automatic watch with day date.
The watch is running in overall good condition but it will need service because it has some problems at the day-date mechanism. I do not have a good watchmaker nearby so I prefer to sell it so other Omega lover to try to fix it.
I will describe best to my knowledge the defects:
So when you pull the crown at position one to adjust the date everything is ok you can adjust the full disk of the date but when the watch runs and the day has past the date do not advance.
The disk with the day of the week advance but it's not properly synchronised..it's half way as seen in the pictures.
The watch keep reasonable time, it has an error of approximative 20 sec/day
Glass in good condition with very minimal thin scratches.
Dial in very good condition as seen in the pictures.
case in very good condition with usual signs of wearing.
bracelet original Omega. I have an 18.5cm wrist size and the watch fit well on my wrist.
Original crown.
I am asking 450 Euro paid by PayPal. I will support the fees. Shipping possible worldwide.
For any question or more pictures do not hesitate to contact me.
Thank you and here are the pictures:

Still for sale..I will consider reasonable offers if you have any.

New price 400 Euro..

Serial number it's visible in one of the pictures..if I read correctly is : 41985801 or maybe 41885901