Gemini:

 

I can't take it to a Samsung repair agent, they won't accept Spark phones direct. Spark won't look at the phone unless it is personally brought in store. Spark stores are closed in Auckland for the duration of L3 lockdown.
As described in my original post I am looking for advice from someone HELPFUL who might know how to repair or at least diagnose wifi/bluetooth faults. Is that you @linux ?

 

I think someone will need to physically look at it to see what's going on; either that or more information (as asked earlier) may be helpful.

Edit: didn't see Maxine's post, that too.