GA VFR 'Call Sign' Randomly Changed

This is “Puzzled of North Wales” :thinking: All of my flying in the sim has been GA and VFR and will likely continue to be. I have recently converted to the Bush League Legends Cubcrafters XCub - great fun :+1: Because that has become my go to aircraft I have adopted a personalised registration in the ATC drop down; that has worked just fine and I had become used to being G-DAVE. That is until last night when I suddenly inherited a new call sign from nowhere - I have become MERLIN 51. After the flight (through the Mach Loop) I checked the drop down and there is no call sign entered. So, I entered a call sign VENTURE 73 and went back to the flight line and called Ground. I had become ‘VENTURE SEVENTY THREE - FIVE ONE’. Can anyone help me to restore my standard GA VFR call sign please as I have been unable to discover where my new ‘handle’ has come from

Thanks

Dave (or G-DAVE :wink:)