You'll be lucky unless its a shed. Raise your budget to £9.5k + if you can, plus £1K+ for any necessary work. Get it checked by an indy or someone who knows these cars.
I know this may upset some E55K owners but I wouldn't like to think I'd pay more than £8,500 (£10k for a 100k miles or less, estate) for a saloon because, even with the best will in the world, even great examples need money spending on them and there's very little on them can be repaired "cheap", new owners should budget at least £1,000 for this, so paying £10k and then throwing another couple of grand at it soon turns your dream car into a major headache.
Having said all that, I do think they're the best value 450+bhp rep mobile you can buy for the money, in fact I'd say that compared to its immediate rivals and those priced above the E55K, the next best choice would be an XFR but they're roughly double the price a good E55K is.
Wonder if it will upset them enough to sell their car cheap
I'm seeing quite a few card around 8k in various states of condition. I've seen a few that have tempted me, but none enough to jump. There have been quite a number starting off at 9.5 and drifting down, still unsold.
Tough market for a scary sounding prospect 5.5 supercharged AMG, what could go wrong there?
Feel free to read my Build thread, It will show you what may not be common what sort of work a £9k e55k can take to get back up to Scratch/ factory spec.