No, I'm not in the business,I'm a Service Engineer so no connection to selling AV gear myself. The £200 was plucked from thin air; I've seen people quibbling over much less. If it's a bricks and mortar store then I accept that they have higher overheads than an online one. IMHO it's not realistic to expect them to be able to sell at the same price, so they have to offer something worth paying the extra for and (in the case of a good specialist dealer I think they do earn that extra, see below). Of course the online one doesn't let you have a demo first, but that's just how it is. It just seems wrong to me to go to a shop and take up their time demoing to you for possibly a number of hours knowing full well that you aren't going to buy from them.
FWIW about 4 years ago I had a home demo of 2 projectors against the one I had: I wasn't sure if it was worth the expense of upgrading since my room isn't perfect. The guy came over and spent maybe 4 hours doing a demo and I was convinced that it was worth the upgrade, though there were two options and the second was much dearer and only a little bit better in my room.
The dealer left me to think about it over the rest of the weekend and since I'd posted my experience on the forum I got quite a few people telling me that I could then buy the projector (JVC HD350 FWIW) for less at various places, thus saving me about £150. I wasn't going to 'stiff' the dealer over that small percentage (remember this was when HD350s were well over £3k) especially as I didn't even know if it was worth upgrading without having a demo.
As it turned out when the dealer rang me back a few days later to see what I'd decided he offered me a further £100 off the HD350, so I was more than happy to go with that deal. Regardless of what his website showed the price as, it only took a phone call to find out that he was prepared to lower the price.
So for the extra £50 I got to buy a projector that I knew was going to work in my room. I picked it up in person after he had checked it over to make sure the convergence, etc was good so I didn't have to worry about it turning up DOA and having to go through the returns process (or worry that it was damaged in transit).
It was a fairly similar story for my recently purchased JVC X35 but I don't think it's fair to discuss any prices as it's still a current model.