To me this would be tricky, and some of what you have written seems odd to me - lacking context I guess…
One Xeon system will have to be replaced at least 5 years early
5 years early? That implies you expect a system to last a lot longer than 5 years - I haven’t worked anywhere that would expect more than 5 years out of workstations/servers. What generation is this system - are you sweating hardware/software that intel would claim is reasonably at end-of-life, out of vendor support and due for replacement anyway? Remember small claims for faulty goods will look at ‘reasonable’ life-span.
New hardware will require Windows 10 upgrades too.
Surely it will come pre-installed? sure, you will loose some time, configuring it, but that’s part -and-parcel of running a business, you always have to allocate time to patching/maintenance etc. so you would have to demonstrate loss of earnings caused by Intel.
plus labour which I normally charge at £250/hour.
Wow, lucky you, I guess you do niche work that only pulls in a few hours a day? Else you are pulling in ~ £10k per 40 hour week which would kind of make this a moot point as you can’t be far off retirement
If you really do earn the big bucks (and power to you) a UK small claims court normally only deals with claims of not exceeding £10k. If you have lost work worth more that that, then it’s a different track for you and I suspect the legal fees could be enough to make you think twice - should you loose.
From the anecdotal evidence I have so far the worst hit stuff is where lots of context switching is happening - databases where page swaps between disk and RAM and parallel processing occurs are some of the worst hit applications. Some of these problems can likely be tuned out or eased by adding more RAM. I have no idea what software you use, but you might find workarounds or solutions that don’t cost the earth?
Good luck BTW; this stuff sucks.