After writing this a month or so ago I discovered in the hotter weather that the aircon in the MX-5 was indeed *actually* shit even when I did turn it on, so got it serviced today. Only had about 1/10th the refrigerant it should've done. More effective now, unsurprisingly.
Antony Ingram
Me: God, the aircon in the MX-5 is shit today, not even slightly cold.
Me, at the end of my journey: Oh. Would have helped if I'd turned it on.