Wondering if there might be any clues about why I seem to have what looks like (heavy ) condensation water under the carpet in the boot. There's no puddle in the spare tire, it's not water coming in from rain via opening boot and I can't see any water entry points!?!

The carpet on top will sometimes get wet too, but since drying that it's not got wet yet over night the under side has.

Does your rear windscreen washer still work?

A connector can pop off the hose and flood the boot

No sorry i should have posted that too,had that go last year so i cable tied that in place, and the one by the cd player seems fine and on damp patch there.

I had similar symptoms last year and it turned out to be the seal around the rear light. I took both lights out and re-sealed them with a bead of clear silicone and it's been ok since.

I find that in this weather I do tend to get some moisture on each side caused by the water draining off the boot lid after heavy rain. In the summer it's not so bad because it tends to dry up but in the colder winter months I keep an eye on it and occasionally dry it with a hair dryer.

got a sunroof fitted? maybe a blocked drain pipe?

When I had my leaks they were coming from 3 areas:

Rear light cluster

Rubber grommet around rear wiper arm

missing washer behind bumper

I had the same issue last year and it was the seal around the rear window.

Do a search under my username and the thread should come up.

My leak was along the bottom seal of the window on the RHS, identified by wetting the outside of the vehicle, opening the tailgate and watching the water drip down the inside of the boot lid, down the rear trim and into the wheel well.

As I had only recently bought the car from a main stealer it went back there and they resealed everything.