TPMS Battery

[Grumpy Goat]

So this problem has seemingly buggered off all by itself and they are working as per normal like they always did.

I hate when those kinds of problems happen because you are none the wiser as to what the real problem is. Good luck and keep us informed if anything changes. With so much electronics on board there is bound to be something to go "funny" from time to time and require expertise more than the average DIYer can fix.