I have Visual Studio 2017 installed alongside Intel Parallel Studio XE 2018, and have tried to use these instructions to select an older version of the compiler to use. However, I cannot find older versions of the compiler (17 and below) under Tools > Options. I also can't find any reference to older versions in the directory C:\Program Files (x86)\IntelSWTools (is this the correct place to be looking?). Any help would be very grateful!
Ah, I think I was mis-interpreting the line "With the 2018 version, you have access to compiler version 14.0, 15.0, 16.0, 17.0 and 18.0" as meaning that Intel Parallel Studio XE 2018 comes with 14-18, rather than it works with previously-installed versions 14-18.
I presume older versions aren't available to install separately with a 2018 license?
Yup you can download and use older versions that are at at the intel download centre but you need to be mindful of what versions of visual studio a fortran version is capable of integrating with.
Every compiler installer that I have obtained from Intel contains exactly one major-minor number combination, e.g., 2017-Update4. You can look up the corresponding release notes to see which hardware-OS-VS combination is suitable for that particular installer.