Recordings suddenly noisy

Hello there
I’m using Audacity 2.3.3 on a Windows 10 Acer Laptop. Not the highest spec but been fine for many VO sessions even while using Skype or Source Connect. I have an AKG214 mic going by XLR into a Focusrite Scarlett 2i4 (1st Gen) which then goes directly into a USB socket on the side of the laptop.
Last week I was recording an audiobook which was fine. Delivered it all except the credits/tags. A few days later having not changed anything at all, I went to record the credits, which sounded fine in the headphones (Beyer 770pro) as normal but there was this weird digital/electrical sounding noise all over the recording when I played it back(please see attached WAV). I tried the mic connections, the other input channel, same issue.

I took a feed out the back of the Focusrite straight into a Zoom H4 without using Audacity and this recording was fine. I installed Audacity and the Focusrite drivers on my wife’s laptop, and that recording was fine.

I’ve uninstalled and reinstalled Audacity on my own machine, Focusrite drivers are latest, don’t have other apps open when recording… noise is still there on recordings, but not heard when monitoring.

Does this sound like a common issue? Any help would be appreciated! I assume from the above steps that the problem isn’t the mic or interface, but something software and/or my laptop. The important thing is nothing had changed since my last successful sessions, as I leave everything set up as is.