You probably don't need an English-speaking Notariat present as you will (should) see a copy of the contract well before you sign anything. You can have this translated and then explained by an English speaking legal expert.
Like doctors, dentists etc, almost all lawyers speak good English here...
We had to have a German translator present 3 years ago when we were at the notary to sign contracts.. you just need to have a friend/colleague with you to translate, inform the Notariat beforehand of who you are bringing, name, profession etc. You should have time beforehand to get the contract checked out legally if you wish.. I would ask and check out everything at the Notariat(should be in the Gemeinde building) as they will speak English and are very helpful. Good luck with your new house .
.. I forgot to say even if you speak and understand quite a lot of German we found that they still required us to have someone there to translate making sure there were no misunderstandings.
As yet I still only have a draft contract, and will move further as soon as the final version arrives. I've been quoted around CHF 3000 for getting the papers translated.
Wow! That's expensive.. we just got a Swiss friend to go through the contract with us and he took time off work to come to the Notariat too.. salt of the earth type as he never expected anything from us.. I bought him 2 extremely good bottles of red wine which he loved.. but I guess if there was something in the contract that were weren't happy with, or confused by, we would have got legal advice. You know you will also get a bill from the Notariat when the contracts are signed and work finished.. if I remember correctly the bill was roughly between 1000 to 1500 chf.. but your Notariat can tell you exactly what yours will cost.