You can never specify a technical project these days. Science and engineering is evolving too fast.
What you can do is specify what you want to achieve and when. There may be an rider such as made in UK only.
By doing this the whole procurement is on the shoulders of the supplier. BUT what it does mean is that the functionality required has to be right and remain unchanged. This is always a problem for an admin civil servant because they are way out of their depth with technology. In the halcyon days of yore our civil service did have scientific groups of an extremely high technical standard. Instead of paying these people properly they were outsourced as companies and sold to private concerns who failed to maintain these centres of excellence.
Go To the top of my comment and start again you are in a never ending loop.
If you have pressed the escape key I can say that I have had to sort out some scientific instrument and contracts and concentrating on functionality really does sharpen up the supplier very quickly in a way that is beyond your own staff.