There is no olive equivalent to the 500 series. Top of the range was CDS/52/135, which was replaced by the CDS3/252/300 as top of the Classic range. CD555/552/500 were introduced as the higher 500 series components.
I think you should be careful what you wish for here. You may find you prefer the sound of @bruss suggested recently serviced 52/supercap/135s to your current 282/HiCap DR/250 DR. However not a bad problem to have.
10k is a valid Budget.
As others said.
CDS2/52/SC/135 (best serviced lately) might beat your current setup.
Active 250 into SBL … a clear yes. But here you might need to pay more than 10k
As others pointed out 52/SC/135x2 were the premium.
Those amps were way ahead of its time, even today many so called high end brands would have a hard time in the Prat department.
Modern hifi soundstage effects bla-bla… is not its strongest, however the “you are there” concert stage feeling is very good.
I’d forget about their CD players of same vintage.
They were superb, in a class of itself, unfortunately no spares and support.
If you can’t find that combo, the following options will also provide superb sound:
72/HC/140 - great option for a small room
72/HC/250
82/HC/250 or 135s
I’ve owned all of these amps with exception of 140, but it’s reputation, and more frequent availability make it a very low risk. Again, depends on room and speakers.
52/SC with the Pots 8 in good nick is the unicorn of all the aforementioned products. 135s are a close second.
I just invested in a beautiful pair of 135s and had fully serviced. They’re staying with me until the world ends or I meet my demise.
With £10k budget you need to allow for speakers, source such as LP12 which with decent used example serviced will cost £2k at lower end. Then cables and racking.
A 72 would be very nice also and cheaper than 82 and 52. Factor in servicing. Use Darran at Class A for servicing, registered Naim service agent, but cheaper and quicker than Naim.
They are almost an identical circuit to the stereo 250 amp; however, with a healthy jump in current, and a few other small differences, I’ve found them to offer a greater clarity on the music, with slightly better bass, and more PRaT.
I went from a classic system to an olive system which I have now had for around 20 years. I like the sound and the aesthetic more. The only thing I have heard that would make me think of straying was an Audio Note system. Just my two pennies worth.