I have a 2008 HSE I purchased during the start of the pandemic. here in Canada. Thought it was reality rust-free until I took it to a body shop familiar with RR. Alias rust lurking under the bottom plastic cladding at the start of the wheel arches. I spent the next week cleaning the steel wire brushing and sanding. Fortunately, the rust had not reached the jacking points.I used a system for hopefully stopping the rust it is called POR-15. It is 3 steps- 1st degreaser cleaner-2nd etching with acid- 3rd the magic hydroscopic paint then Fiberglas painted and put over small rust out holes. I hope to report next year my be loved Harriot rover is not rusting

Today I removed the plastic sill protector and the wheel arch liner. By the time the wire brush had done its job, holes in the bottom of the rear drivers side passenger door arch and one underneath which was originally the small hole that the small plastic lug goes in to secure the sill cover !

Copious amunts of rust treatment now on the cleaned off metal surfaces and tomorrow the welding and filling begins. 13 years old and in this state. LR hang your heads in shame.

Click image to enlarge

Click image to enlarge

These photos are very reminiscent of my RR. both sides I am sure. The good news is we caught it before it got to the jack sites! Your repair is much more substantial. then my patch. When I first discovered the rust I was going to do the patch and then leave the moisture holding plastic cladding off, but my wife thought otherwise. I will just unclip the cladding enough to rinse the road salts off. Have you thought of waxol both rear quarters ? On your side of the Atlantic, a gentleman did it to a 125000 sterling Westminster. I did it to mine with the POR-15 since both wheels off made easy access. The gentleman`s Westminster did not have one additional screw at the top of the arch to hold the plastic wheel liner in place.

Will be waxoyling every orifice before putting sill cover back. Luckily the place where the jacking pad fits was rock solid.

Plenty of more information on rusty arches here:

https://www.fullfatrr.com/forum/topic54121.html

fanders ---------------------------------------
2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

I am so fortunate to have found FFRR, of course, my terminology is a bit off but we are on the seem page

Holes welded, vast amounts of waxoyl applied inside and out
side of sill following paint. Black plastic sill trim back on but struggling to get the black plastic clips that go on the underside of the sill to keep it in place ( not the white clips that push in to the sill along the side.)

Click image to enlarge

Try ANR2224, used on most of the LR models over many years to fit plastic trims.

DaveK wrote:

Holes welded, vast amounts of waxoyl applied inside and out
side of sill following paint. Black plastic sill trim back on but struggling to get the black plastic clips that go on the underside of the sill to keep it in place ( not the white clips that push in to the sill along the side.)

Click image to enlarge

I have recently checked my 2010 inc taking out rear wheel arch liners and plastic sill cover and not a single spot of rust

Xray charlie wrote:

This was the extent of rot on my 2093 car, both sides and rotten boot floor, I’ve decided it’s too much work so sadly scrapping it 😞😞😞

Classic888 wrote:

Try ANR2224, used on most of the LR models over many years to fit plastic trims.

Just about to embark on repairing my 2004. I have a couple of questions I would assume if enough pressure was applied here a hole would result, can anyone comment if this would be a UK mot fail?
I see the part number for the black clips for the underside of the sill trim in this post, does anyone know the part number for the white two part clip for the upper edge?
My second photo shows the cavity was applied to the rear half of the near side arch, I can only assume the lower front of the arch where it joins the sill received the same generous amount 🤔😟

White clips are EYC000310 or may supercede to DYC500080.