Has anyone used 2SO in their diesel Yeti?

On various forums/fora there have been many claiming great benefits such as reduced noise improved economy and cleaner when stripped down, applying to DPF and non-DPF equipped vehicles.

I only use Autol Desolite DX-W

One issue is that you are adding ash-forming additives directly to the fuel, so they will go down the exhaust and into the DPF where they will be trapped. Regens don't remove ash, only soot. Once the DPf is loaded with ash, there's no alternative but to replace it. There will always be an ash stream down the exhaust from engine oil incidentally burnt in the combustion chamber, but adding oil to the fuel guarantees it and will shorten DPF life. I'd guess that at the dosage likely to be used this would be a small incremental additional, but it is an addition nonetheless.

If it was required then the fuel companies would include it in their fuel, and they don't, therefore I shall be saving my money and not bothering.

The only purpose to use  2SO in 4S engine is for fuel supply chain, especially injectors: oily fuel prevents wear and reduces "noise" for sure. Rest of the 4S engine is much better lubricated than any 2S engine ever and 2SO just can't improve anything. To achieve noticeable long term effect you should use it all the time. Downside is the expense and risk to block DPF and IMO there is clearly more to loose than to gain, so my advise is: don't bother.

"If it was required then the fuel companies would include it in their fuel, and they don't, therefore I shall be saving my money and not bothering."

That's why I do not use ANY fuel/oil additives + saving money of course.

Some use the ash less and swear by its cleansing properties (strip downs) among others incl reduced regens, hpfp lubrication and quieter engine, and of course economy.

Lots on the Freel2 (LR2) forum and Watercooled (diesels) as well, certainly divisive if you like that sort of thing.