Sterling power product - power pro Q. Had a electronic guy look at ours but it's a major problem that cannot be easily fixed. We were very grateful of his help ( a fellow overlander) as Sterling power's response was 'It either works or it doesn't!' That was from the technical assistance team!! Real assholes.
Don't think we will find the technology over here. Everyone points to Buenos Aires or Santiago. We suspect as a 'get rid of us' ploy!
Have managed to find a £20 make do inverter but it is a cheap emergency option until we find a good one.