Frankly, anything above 30chf is usurious. Replacing the battery is trivial and shouldn't take more than a minute, two at most, and the battery itself is just a few chuff.
Did you consider DIY?
Order by mail, battery (costs 0.50-8chf, probably 3 or 5chf) plus "Uhrmacherset" (7-20CHF, probably 10chf), 8chf postage (all prices from pearl.ch), the tally seems unlikely to exceed 25chf. Or pick up the items in Spreitenbach and save the postage. Next change will be necessary in a few years, at which point all you'll need is a new battery that costs 3 or 5chf.
Make sure you know what you actually need, plenty videos on youtube that tell you. You probably won't need to open the bracelet so no tool necessary. The user manual for your model available on this page
tells you what battery make you need.