Seamaster SMP300 Bond (quartz) options?

I have had my Seamaster Bond for over 22 years, my first decent watch, it has the 1538 quartz movement (I think) the negative battery gold 'leaf' terminal has detached and I have bodged this for 2 battery changes but now cannot. My question is what options do I have for repair

1. Omega Service Centre seems it is £450 in the UK and they apparently change out most things including the movement I have read, my question is if Omega do it will my issue be addressed for the flat rate of £450 given they swop out movements etc? The watch is mint condition otherwise.

2. Is a third party repair viable installing a new negative terminal? Been told an ETA 255 461(2) could be fitted but think this would devalue the watch given it won't be stamped as an Omega movement?

Thanks.

Excellent help and info much obliged. Thinking it is superluminova lume as it was early 2000's purchase and the lume is amazing to this day. I think I will bite the bullet as I have not had anything done to this example in all this time. Bezel is good, no fade, some prefer originality, will see on that if they ask.

I see the ETA 255 461 are advertised for $300 on E-bay. So $150 extra for Omega service seems reasonable.

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