Some brands ignored ?

That's probably not a bad reason, I've never heard of any of them.

The general rule of thumb is if a manufacturer doesn't send their product to WHF they can't review it. Manufacturers that don't sell in the UK are unlikely to send their products to a UK magazine for review.

Never heard of any of them either...

Prima Luna and Audio Analogue have been reviewed a fair few times by WHF.

Vincent/T.A.C have the same distibutor or sister companies IIRC.

I've heard a few Audia bits when they were briefly distributed via Henley Designs - good sounding stuff with Bryston build quality. High prices though, and lack of public awareness probably saw to it that they didn't last long over here.

With some of the smaller or less well known brands distributors dip in and out of the UK market – we only try and review products that are available for sale and have official UK distribution.

And Epos, for exemple the new range Epic and Elan...? No reviews wath so ever... 

I wouldnt want to start a conspiracy theory but I have also observed that there are brands that almost all their products are always reviewed and other well known brands that you are lucky to come across a review of them. Does this have anything to do eith the expenditure of these brands on advertising on WHF?

If you look at brands like Onkyo and Yamaha they are always reviewed and they almost always come out with a very high star rating.

Ahem...

http://www.whathifi.com/review/epos-epic-1

WHFI rely on companies letting them have a review product. If a manufacturer isn't forthcoming there's little they can do. (Occasionally they borrow a product from a local dealer and the odd occasion they will go out and buy a product: Gotham interconnects and AVI spring to mind).

but I have my conspiracy theory, and not only covers the What Hi-fi magazine, but the main audio and video magazines, and is not related specifically to the fact or not to advertise in their pages ...

Although this fact may have influence, but I can give you an example that does not fall in advertising ...

My theory is related for example by ranges:In the magazine What Hi-Fi, for example the range of monitor audio silver is very present.

Already in Hi-Fi Choice did not see a single mention of the range silver, but gold range as the award "Hi-fi choice" which is the same as the five stars of "What Hi-Fi", and the gold range (GX200) was gold only 4 stars.

In "Home Cinema Choice", the set GX for home cinema, had 5 stars ...

I think every magazine advocates a range of a specific brand...
and each magazine has its favorite brands ...

I have said!
Now here comes "EDIT" ...

exactly what I just said in my previous post ...
like to see a review of the Epos Epic 5, for example ...

I wonder if it is really about offering your product for review as suggested above by one of the respondents. There are very good brands out there that beats the most reviewed brands hands down. Are you telling me that these brands would shy away from offering their products to be tested and loose out on the free publicity? I don't think so. The association of the brands to the magazines must have a bias effect on who gets reviewed regularly and how well they are rated. 

You use many examples: They recently tested PMC 22 but that doesn't mean to say they'll test the 21. They've never tested TB2s or Focal 714V...

Exposure 2010S amp and CDP was tested but not the 3010S CDP.

Can't expect them to test every model from every brand. No conspiracy. Just practicality.

Check brands like Yamaha. Almost the entire RXA range has been reviewed whereas other brands are hardly featured so I doubt it hAs anything to do with practicality 

Is it now...? 

The magazines job is to sell reviews.  People want to read about kit that's available to them. More people have access to MA for instance than Epos, more people are aware of MA than Epos, so logically writing about MA is more likely to sell magazines.  No conspiracy, just common sence.