A friend of mine is opening a Cafe and they have asked me to fit the kitchen. They have not got a clue, apart from randomly opening all the boxes and losing half the fixings they have ordered a worktop that is exactly the same width as the units with no overhang. They are away at the moment, trying to rescue the situation I have rang the company and asked them to check the order to find what they have bought and tell me if an upastand is available and if so how thick it is so I can set it up to fit the sink ect, they could find the order but wont tell me how thick the upstand is due to data protection, really.
That sounds very like a Elf and Safety Jobsworth approach. Suggest that you purchase all the items you think you need on a sales or return basis, and suggest they pay return carriage if you dont require them , or something like that. So that it hurts the supplier to not provide the info... Explore the negative space, they dont have to answer the question, but arrange a scenario where you find the answer by causing them loss if they dont help you.