There are two ways in my experience that you can get a home demo from Richer Sounds. The most honest is to go to the shop and explain that you want to try the gear and if they haven't got any to demo they will get it. You pay for them and they will then let you take that already "open-box" set home to try. If you like them, you return them and they swap them for sealed boxes. If not, you return them for a refund (this is certainly the case with the London City branch - you may need to discuss this with your local branch). This is better for them because it doesn't create another set of open boxes that they have to then discount.
The second, arguably more disingenuous way is to mail order them. You can then return them under the consumer protection legislation (what used to be distant selling but is now wrapped up in other regs) for a full refund provided you've taken all reasonable steps to unpack and repack all items undamaged. This is less desirable from their perspective because it turns a pair of sealed boxes into a pair of open boxes, if that makes sense.
I've done both in the past, the latter was quite recently when I bought a CXN streamer and decided I should have gone for the 851N and so returned the CXN. They were completely separate transactions, in fact I returned the CXN to a store after I received the 851N by post with no problems but they did then put a sticker on saying it was a return to be discounted.
For what it's worth, I have an 851A and I like the sound. I may add an 851W in due course though for the extra horsepower, and like you I've not read a bad review of the 851E/W combination, especially for the price.