Overnight Parking - M25 South, Dartford / Clackett Ln area

Hi all

I’m finding myself frequently on runs from Stoke down to Bristol, then Southampton, then Brighton - then jumping across to South Essex.

I usually try and make it to Boreham / Braintree (both good for parking) but am usually hitting the M25 at rush hour and rarely make it before my hours run out. Can anyone recommend any good / reliable parking near the M25 Corridor from about Junc 7 of the M25 - through Clackett Lane area - to as far as about Dartford? Problem is at rush hour I don’t really fancy venturing off the M25 to look for places as the traffic is terrible. I’ve looked at google maps but that part of the country is a bit foreign to me. Doesn’t have to be a truck stop, just a reliable layby / safe industrial estate etc would be fine. I refuse to give a service station £35 to park in a noisy carpark and not sleep.

Many thanks!