water water everywhere but where's it coming from

After the other half had finally had enough of getting half a cup of water on her knee the first time I put the brakes on after setting off I decided to try and stop the water leaks. The water on the knee was solved by sorting the seal round the passenger side alpine window which had lead to water accumulating in the interior gutter every time it rained.
There is still a small pond though on the rear carpet right underneath the rear door stretching perhaps two feet into the rear compartment.
The water ingress manual suggests having a 2 qualified techniciens sitting in the car whilst I hose it down for 5 minutes but I don't happen to have a couple handy at the moment.
What do you reckon is the point of ingress? The rear window , the port hole thingies, the spare wheel holder or is it coming through the joint in the body tub. Or maybe somewhere else? It's a 2003 county station wagon.
Any suggestions welcome.

Water was running in at the base of my rear window, mine is a 1995 300 tdi though. I ran some silicon round the window lip and it's fixed. You could see quite easily dripping in. Otherwise I can only think of tub capping joint, or rear door rubber.

Do you park on flat ground (exactly flat) or is it generally parked at a slight angle - which way? Could be condensation on the roof running to the back door and dripping down....

Thanks. And yes I do park slightly nose up so that's another thing to investigate.
Got some black mastic so I'm gonna seal everything and see what happens.

Dry it all off, talc powder all over the shop and get hosing, water can travel quite some distance form where its found

Be sure where the water is entering, don't seal everything up on suspicion. The previous owner of my TD5 did exactly this - bad silicon everywhere. More problem than solution. If the sealing isn't perfect, water will still enter, but it will be harder to trace. And stay underneath your new sealing eating away at your beloved metal... my cappings where almost gone because of overeager sealing.

Got the front sorted out, eventually.

So - if the door seals look suspicious, replace them and apply the appropriate fixes from the water ingress manual.
Keep a small flashlight ready, so you can look for water entry while driving in the rain.

I applied tape to suspicious areas and checked for improvement. Resealed only confirmed areas. Got 97% of the water, that way.

My TD5 does this - I tried for a while to find the leaks, but bought a car cover instead, not quite as stupid as it sounds as I don't use the car everyday.

Have'nt you heard about the cat in 3different cars ,they found the cats dead in all the cars except the land rover,it had escaped ,missing, gone. That's the reason you have leaks