For anyone looking for a low rust rear hatch there’s one on eBay.

https://www.ebay.co.uk/itm/197261220496

Certainly better than my existing one, but I’ve gone down the expensive route, so thought this may help someone.

Can’t imagine it’ll hang around long.

Can I ask what the expensive route is?

Mine is currently at the same stage as the one in the listing. I'll need to do something soon.  ---------------------------------
2008 L322 Supercharged
2007 Porsche 987 Boxster S
2024 BMW iX3

I paid £450 shipped for a rust free example which is immaculate, but the wrong colour and has the wrong glass, so some bits to do to get it sorted.

It was described as having tinted glass, which I took to mean factory tint, but turned out to be aftermarket. The tint film was damaged on arrival, so got £100 off in the end.

Going to have a go at doing the glass swap over from my existing tailgate myself. Doesn’t look too tricky.

Ah, I thought you were going to say you had it repaired.
I wonder if thats possible? ---------------------------------
2008 L322 Supercharged
2007 Porsche 987 Boxster S
2024 BMW iX3

I have also been looking for a long time ( Five Years or so ) for a nice Sumatra Black upper tailgate, have even been to see a few, but they are all worse than mine, the trouble is the longer I leave it the less chance there is for a good one to come along ( rust free would be a bonus )

My paint guy told me not to worry, and when I go on a long holiday (more than a few weeks ) that he will will take it off and sort the rust along the tailgate edge and re-paint for me, along with ten or so other minor paint corrections that need doing - the joys of having a 14 year old L322

What we really need is someone to take a mould and make a fibreglass one. ---------------------------------
2008 L322 Supercharged
2007 Porsche 987 Boxster S
2024 BMW iX3

Having seen inside my totally stripped new one, I can see where all the potential water traps are. Although there are two drain holes, there is also the long seam between them that water can sit in.

The paint is pretty much overspray from the outside, so no thought to rust prevention.

I would say that the only way to repair these is to take off the tailgate. A localised reoair generally only fixes what you can see, not what’s lurking further along waiting to pop out.

You’ll be very lucky to not get rust coming through again if you only do a local repair. A bare minimum would be cutting out the old rust sections, welding in new metal and dousing the inside - first with rust converter and then rust preventer.

I wouldn’t rely just on the 2 drain holes either. The lower lip corners have a slight hole in them and can let water out, so on mine I’m going to slightly open out these corners so water can drain freely and also make sure I identify any areas of water ingress and make sure they’re water tight.

you say they are "drain holes" at each end of the tailgate, but that was not the intention for them, they are just part of the steel manufacturing process and they can be blocked up or welded shut after using rust prevention products inside the cavity to stop rust getting a hold from the inside in the future ( which you are going to do with your rust free tailgate )

some of us have taken off the number plate light housing ( four screws ) and squirted loads of rust eating and rust prevention type products into the cavity without taking off the tailgate and luckily the excess can easily drip out of those drain holes.
NB on mine I left the lower tailgate open and used old towels to absorb the drips.

I was told ( maybe wrongly ) , that the reason the upper tailgate rusts is because water runs down the roof and down the tailgate and collects between the upper and lower tailgates.

The suggestion of a mould and manufacture is really interesting. I think it would be good to do it in good quality steel, but how expensive would it be to do that?

I think any good repair should take the glass out anyway, so you are probably doing the best you can Jonny.