SIM card not detected on Lineage OS

I installed LineageOS on my OnePlus One (bacon) a few months ago. With Covid-19 lockdown it was weeks before I noticed that the SIM card isn't being detected. I thought it might be damaged, but EE sent me a replacement, and inserting it changed nothing. Could it be an absent LineageOS driver? Is that likely? If so, where would I get it from? Perhaps there is a problem with the SIM connectors? As there is the "NO SIM card" message, I assume that no other diagnostic software can communicate with the SIM when it is in such a state.