how serious is a line/earth res of 0.91Mohm?

0.91 Megohms =3D 0.91 million ohms, right? 0.91 million ohms =3D 910,000 ohms, right? The initial leakage, if that is the correct figure, at say, 230 volts =3D 230/910,000 =3D 0.000257 amps, in other words 0.25 milliamps or one quarter, of one thousandth of an amp. So it won't operate anything or use any appreciable amount of electrcity, or cause anything to heat up and burn. For now! BUT; it should be identified which circuit, or which branch of a certain circuit it is, tracked down and repaired. Agree it could be almost anything from a damp junction box, house condensation in an outlet box in a cold outer wall/bathroom, slight damage to a buried wire, deteriorated 'old style' wiring?