Sure thing, thanks for looking into it.
I’ve just done a further test – holding RMB + LMB together fires lasers and allows me to move the ship (expected and correct behaviour) – releasing LMB but keeping RMB held causes the in-game cursor to reappear (as if RMB was not pressed, so ship movement isn’t controlled) – pressing LMB again causes the ship to fire lasers and move again (so correctly behaving LMB + RMB together).
I’ll send you an email now.