Took my MacBook to the store to get fixed. Fingers crossed it’s a simple thing and not the motherboard. Quick update on using the iPad Pro as a MacBook replacement - it’s utter misery. While the iPad excels at drawing and marking up, it’s bollocks for coding/debugging website designs and publishing a newsletter. It can be done. It’s just a total ball ache - something you can put squarely on the software not the hardware.