Looking at renovating our kitchen i.e. mostly keeping carcasses of cabinets and the granite worktops and looking at replacing doors and appliances plus solving am awkward corner issue.

Does anyone have good experiences of kitchen manufacturers calling out and giving good service, plans and reasonable prices?

Am not actually answering your question, but....our builder actually made up the additional carcasses and doors we needed when we did our kitchen reno - we had odd sizes and I wasn't prepared to pay for a kitchen company to manufacture something unusual. And we had success in repainting our existing kitchen door/drawer panels - 3 years later and they still look good.

IKEA seem to be solid for kitchen supplies at a "reasonable" price by Swiss standards...

Good luck!

Tried to do this some 7-8 years ago:

called 3 or 4 places to come and give a quote. Only 1 turned up and the other guys just said that it was not worth their effort.

The 1 who turned up gave a quote which was close to getting everything new anyway. So we ended up with a new kitchen. In switzerland, labour costs are high so if they have to spend hours fixing something old, it may be cheaper to install something new.

Or doing it yourself.

Before I rented the house my kitchen was renovated by this company from Zürich area

https://gennaro-umbau.ch/

they have some very skilled people which are now helping me with the bathroom. Maybe you can contact them and ask for a quote.

I don't know about your awkward corner, but I have a 45° wall in my kitchen and they adapted the standard furniture.