They say the original is not in stock and have offered a different adapter. Only a catalogue picture so far.

I've been dealing with a connector facing into a fixture on an allegedly equivalent adapter. Give your installer the full assembly comparison before accepting a substitute. The top view can hide the bit that ruins the fit.

Did they actually say the original cannot be supplied, Rosa, or only that it is not on the shelf?

Ask that directly. Delayed and discontinued lead to different choices.

Only not on the shelf. I have asked for an original-item supply proposal and complete substitute details. Installer has the controlled drawing of our current assembly.

Good. Get a matched local option priced too, if one is practical. Not a recommendation to buy it in annoyance, just something real to compare with another indefinite wait.

Grace, yes, and ask about stock when they price it. We had a lovely alternative quote whose actual item was no nearer than the original one.

Original can still be made, no confirmed lead time. A local source has quoted a matched adapter and checked availability. Purchasing is asking the seller for a shortage-credit amount before choosing.

Does that local price include everything in the missing spare line, or only the adapter plate?

And delivery. Small omissions add up.

Complete agreed adapter kit and delivery included. Seller's credit proposal is lower, and the difference is visible in our comparison. Purchasing has not accepted either option yet.

At least it is a decision with numbers now. Please post what you choose; the extra cost may still be worth it, but it should stay part of the story.