I've made good use of the EM downtime
Took the grill off yesterday evening, and slapped together my quick & dirty proof-of-concept grill block using black tape.
It goes a bit further than the 70% Volvo DrivE grill block, but still lets through some air to get to the battery and into the engine compartment as the intercooler is on that side as well.
Time to take it out for a test drive, the weather is rather hot again after a cool spell - we're back to 26-28° C, more than 10°C more than earlier this week.
If it works well, I'll make a more aesthetically pleasing permanent block.