The Duchess has been off the line for a week or so because she decided that 6 cylinders are quite enough from cold. They do come back in when the engine is warmed up but it's a very nasty sounding idle/drive with 6!
Seeing as she has had new plugs and wires a couple of months back* and 4,7 are on the bottom half of the same coil - I'm wondering if this could be a coil pack issue. However, it seems a bit weird that only two of the four are missing. Or is that normal when a THOR coil pack starts to fail? Are they really two twin coils in a single box?
Or maybe it's something else entirely?

The codes are as you'd expect - catalyst damaging misfire 4, same for 7, then the multiple cylinder misfire error (logical) and sometimes adaptation out of range if I've been driving it on 6 for too long.

*which cleaned up a misfire on #2

Yes, the Thor coil packs are two dual ended coils in one block, so yes, it does sound like it's new coil pack time.

RightO, thanks Richard!
I'm guessing there will be some really convenient bolts to find... the wires on their own were "interesting" for my shovel hands.

Ack, initial search reveals Britpart for ~£14 or.. not much else. Does anyone know of any decent coils out there?

Ahh original LR https://tinyurl.com/y9rropuz for... quite a bit more. £65/£78 depending on VAT.
Bollocks to Britpart, it's payday on Friday.

Should I do both?

I'd go for the Intermotor or Allmakes if it were me

https://www.lrdirect.com/ERR6045-Coil-Pack-4-Plugs-Ds2-V8-2-Requi/

Bolts wise on a Thor there are 4 bolts holding the bracket on, two go into the upper manifold and are easily seen, the other two are on the lower edge of the bracket right at either end. I think mine had 2 X 8mm bolts with a hex head, and 2 X 4mm allen key bolts (had mine out ealirer this week to do the valley gasket)

On a p38 you might have enough room to get in and undo the bolts that hold the coil pack directly to the bracket, you can't do on the Disco. Whole thing will slide out of the side with a bit of a fight and manulipation, though I think on a p38 you have a bit more space there.

I've replaced both of mine, one was a Delphi that went in, other is a Bosch. I do have some Britpart ones that were purchased without realised that was what was going to turn up, and at least one of the plug leads was a real struggle to get to go on (pin was too large), so I decided against using them at that point as I didn't really fancy taking them out again soon. Mine came off eBay I think at the time.

If you look at the plug on the low voltage side, there are 3 contacts there, one is +12v the other two are grounds, Its a wasted spark type system if you want more info on how it works as such.

Thanks Brian, that's good info - good enough for me to take it to the local indy :)
They're fine with me bringing my own parts so I'll stump up for an hour or two of labour. I'll print out the wiring chart for them too, it seems only fair.

I had a wiggle of the wires to make sure it wasn't just a loose connection and there's possibly enough room to undo the screws holding the coils to the bracket, but you'd need a stubby screwdriver or a screwdriver on a ratchet handle. I think they're flat screws too, not cross-head, just to make it that tiny bit more annoying.

The Bosch coils are easy enough to change, but they won't come out of the bracket whilst on the engine - it's far easier to do them with the whole coils and bracket removed.

As Brian says - 4 bolts - if they are even all still there, and then they lift up the back of the engine, if you don't have too much LPG stuff down the back.
I remove then with the HT leads attached as it's easier than trying to unplug them down the back of the engine. Swapping the coils in the bracket is easy enough on the bench, and then refit HT leads before poking it all back down the back of the engine.

Shouldn't take your indy long to do... worst case if they won't come out, you may need the plenum bananas removed for access.

Grrr, now the misfire has migrated to the other side :/ 8 and 2
I'll replace both coilpacks and go again - Hope that fixes it.

The knob jockey that wired my LPG pipes covered the coil packs, and ziptied the pipes to the HT leads for some reason..

Blooddy muppets!

Coils replaced, misfire gone - no codes.
Hurrah!