VS CUDA 10.2, No CUDA toolset found

We are trying to port our legacy use of find_package(CUDA) to a more modern cmake using CUDA as a language, using in one of our list files.

	find_program(CMAKE_CUDA_COMPILER NAMES nvcc nvcc.exe HINTS "${CudaRootDir}/bin/" "${CudaRootDir}/nvcc/bin/" NO_DEFAULT_PATH)
	include(CheckLanguage)
	check_language(CUDA)
	enable_language(CUDA)

It seems if we have CUDA (10.2) installed, we can configure without a problem, but if we just use a copy of CUDA, and tell cmake where CMAKE_CUDA_COMPILER is, it complains with following error;

See also "C:/GAIA_builds/enLfPmZQ/0/simphony/Simphony/build/CMakeFiles/CMakeOutput.log". ERROR:main:CMake Error at C:/Program Files/CMake/share/cmake-3.17/Modules/CMakeDetermineCompilerId.cmake:367 (message): No CUDA toolset found. Call Stack (most recent call first): C:/Program Files/CMake/share/cmake-3.17/Modules/CMakeDetermineCompilerId.cmake:32 (CMAKE_DETERMINE_COMPILER_ID_BUILD) C:/Program Files/CMake/share/cmake-3.17/Modules/CMakeDetermineCUDACompiler.cmake:72 (CMAKE_DETERMINE_COMPILER_ID) CMake/ThirdPartyCuda.cmake:51 (ENABLE_LANGUAGE) Networking/CUDAInfo/CMakeLists.txt:5 (USE_CUDA)

Is there any workaround for this or is my conclusion right that CUDA must be installed (in a standard way)?

Is there some variable like CUDA_ROOT that we should set to make it work?

The reason why we copy CUDA is because have so far treated it like a thirdparty library/tool, which we keep in a repository and every developer checks out the exact same version (via script).