You've got sRGB files you've imported into Lightroom? In Develop>Calibration, you'll only see "Embedded" not the actual ICC profile. It's still sRGB and you can create a smart collection to sort by color space. It be nice if instead of Embedded, we could see the actual profile but for whatever reason, we can't. Going the other direction, check your color settings to ensure it's not stripping the ICC profiles. LR always embeds an ICC profile in rendered images. So it's not LR.
I only open RAW files in lightroom, with the camera set to sRGB. The problem has been solved by D Fosse, who correctly advised my to go into preferences - External editing, where the colour space was still set to the default. Changing that has solved the problem.
Thanks for replying
I only open RAW files in lightroom, with the camera set to sRGB.
FWIW, setting the camera for sRGB has zero effect on the raw. That only affects the JPEG (and the lie of a histogram on the camera LCD). But sounds like you've got this sorted out which is all good.