Thanks guys, that confirms what I was thinking, I just hadn't had the time to check it.
I have the original SIM cover with the single solar panel in it that I removed when fitting the daytime FARS so I'm sure I can find some way of using that on it.
I've also got a spare temp/hum sensor that I wanted to fit, hence the original question. It's also handy to know that I've now got a backup if anything happens the ISS SIM.
I've noticed this morning that the outside temp is occasionally going to ---.- but the humidity is OK. I've re-established comms between the ISS & the console but that didn't change much. The temp/hum sensor is one of the later ones as it was replaced about a year ago.
When it stops blowing a gale out there then I'll check the connection on the SIM and clean the sensor & plates but has anyone seen this before and have any ideas of a solution?