...game boots awaiting ld player.
You're lucky, it's the easiest fix!

Because an original Philips 22VP932 LD is now *almost* impossible to find in a *working state*, I strongly suggest to go that way :
Matteo's
EURO DL CONVERTERIn short it's a custom board that translate serial commands from the original board to a more modern, fast and reliable laserdisc player (I'm using a Sony LDP 3300, still not too difficult to find nowadays). So the game is still powered by the original boards and a real laser disc player!

I went that way more than 8 years ago, and it still working fine

(see
here).
For the price, the nice & fair range for a collector would be 500-700€ with all the spare parts you have. Of course you can expect more, because Dragon's Lair Atari version is not an easy game to find in Europe. Because of the LD problems, most of the operators didn't keep them long...
Good luck for the sale.