Agreed. £40 for the ABS module to be tested and since I had one fail on an E39 and a mini one I thought I would get it checked. If it’s not that then I’m not sure what to do.
I have seen videos on how to check the network with a multimeter via the diagnostic socket but I’m not an expert so we will see.

Update.
The ECU testing company called today. The module was faulty but is beyond repair apparently as it has an internal hardware fault or something so they are sending it back. £19.
So I’ve had to source one off eBay and hope it’s ok. I did that with my E39 10 years ago and it fixed it so fingers crossed.