The S8 is now back home with me - a total of 8 working days turnaround from cats coming off to car being completed. They were shipped on a Monday, arrived Weds in Germany and as far I can tell were probably return shipped on Thursday, given that they turned up on the Monday morning in the UK!
As I mentioned before the cost of re-coring both cats, including return delivery was just under £720, plus £30 to get them to Germany, so call it £750 all in for the cats.
Removal and fitting, the cost of which you'd have whether fitting new or refurbished, came in at £270. Lambda probe was the only unexpected element at £110.
So all in I've spent £1,130 to have it back how it should be....
Sounds a lot, but if I'd gone the OEM route I would've spent £950 for one cat, plus probably £180 for fitting, just for the offside one so exactly the same spend!
I haven't driven it far yet, but the exhaust now sounds a lot sweeter - I suspect the failing cat was upsetting the exhaust balance. Not having a distinct rattle coming from under the car is also reminding me how smooth it used to sound!
It will be interesting to see if I can detect any difference in performance once I've had an opportunity to warm it through properly and exercise the engine a bit more